Sveinbjorn actually does speak Icelandic, and I've been looking to learn it as well just recently, so you haven't quite picked something obscure enough to ensure no potential corrections. But he's really quite nice, so he wouldn't dream of being rude about it, even if he were so inclined.
I often pause Skyrim, for hours at a time, to write out a scene I just played in a couple of minutes, because the words are there, already narrating, and the scene has huge potential, so I'm definitely on board with all of that. And I dislike playing if someone else is present, because I feel like it prevents me from really getting into the headspace of the character, and then everything is 100% more shallow than before.
But what I'm hearing with your writing, is like your being caught somewhere between "OH, I want to make this thing immediately, now, now, now, GO!" and "I want to plan this thing! HNNNNNGG!", and they're not fundamentally oppositional. I have a road map for my fan fic (and for any story I write), because it helps keep me focused. You may find beautiful description in exploration and wandering through your characters, but when it starts to wander away from the narrative goals, it becomes unneccessary, distracting, and generally bogs the whole thing down. Knowing where I need to go before I get there means I can more easily let go of what doesn't belong, and I can keep my characters consistent throughout.
That doesn't mean going back to edit in changes, foreshadowing, or justification doesn't happen, it just means it's less likely to change everything already established to support something better later.
I say, try to give yourself the time and patience you need to make a road map, even if it's just a skeletal structure of a story, and fill in what you can. It can always change as you start writing, but having it ahead of time does a world of good for those who benefit from the structure, even a little.
For the last question, you want to take it easy on description. Descriptions are important, because they let the reader view the world through their own minds, and ride along with the characters and their experiences. That said, description needs to be pretty light and non-specific.
As an example, I'm going to write some descriptive scenes. The first will be with as much attention to detail as possible, without sacrifice to a sense of narrative. The second will be detail overload, and the third will be brief, just for color and pacing.
Example #1: Horace Awaits Duke Byron
Horace waited in the study as requested. Duke Byron did not often allow visitors to his study, but it was rarely a pleasure to be invited.
Despite the luxury around him, Horace felt uneasy in the sumptuous burgundy-draped room, with its gilding and dark stained woods.
The floor was made of exotic teak, stained so dark it appeared black in the angry light of hearthfire. At least, that is, where it could be glimpsed beneath the various rugs Duke Byron had used across the floor.
Each rug represented a different culture, but coming from the same country, all bore a similarity in design. They appeared to use motifs, more floral than geometric, but to say the designs looked like flowers would be inacurate. They looked like weapons, and the tendency toward burgundy -- or si'equen'oc, as the natives called it, which happened to translate to "blood" rather easily-- only deepened the imagery. The "floral" designs alternated with those that looked vaguely of human body parts, but it was only when Horace stared very intently that he could begin to discern a horrifying pattern to their placement.
Feeling too near the brink of a realization he did not want to have, he turned his gaze away, but there were few places in the dark study to offer refuge. The walls were dominated by built-in bookshelves, and filled to the brink, nearly every one. If one only glanced at their presence, they would speak of a man who was increadibly well read, but even a cursory glance at the titles would quickly reveal him for what he was. Books on the occult lounged against manuals for the removal of flesh. Recipe books crowded Shamanistic histories, and everywhere the symbol for "alchemy".
Duke Byron's desk did little to settle Horace's stomach, for when he let his eyes trace the complex and intricate carvings, he discerned the twisted and lewd forms of man painfully bent into those of beast.
--- [ end ] ----
Example #2: Sarah is a Witch
Sarah looked out the window.
The sky was a bright azure span, stretching to the horizon and beyond. The mountains tried to pierce the sky with their mighty peaks, but even with their dominating height, they stood no chance. From her window, the mountains looked blue, with the occasional patch of green so dense it almost looked black. If she squinted, and the sun was behind her, she could sometimes make out the shadows between tree clusters, but playing that game always strained her eyes, and left her with a migraine.
White, fluffy clouds drifted across the sky on a lazy breeze. Vapory curtains stretched between them, and looked much further away than the puffy clouds taking shape on the wind. As she watched, a formless cloud took on the appearance of a rabbit wearing a pimp hat, and sprinting for his life. It evolved, though, the face stretching until it looked more like an alligator swan diving through another cloud. Several other clouds merged into a giant cloud amalgamation, with unicorn heads, and train engines devolving into marshmallow faces and sleeping kittens.
Their shadows drifted across the field, as cool and lazy as the clouds themselves. The tall grass moved in waves like water, lapping at the shore of the forest around her cottage.
Her gaze shifted to the window sill. The wood had been rough ages ago, but now it had been worn smooth. It was unstained, in the traditional sense, but had a nice kind of patina on it from centuries of elbows leaning, and pies cooling, and hands resting. The wood's grain was nice and straight, and the builder had lain it true, so that even the most discerning eye would know he had been a master at his craft. A little lady bug crawled along the inside edge. The shells of her wings were cherry red, and each one had two little black dots. Six tiny legs carried her across the sill as her bitty antennae quested about for her quarry. She didn't have much of a shadow, with the cottage's own shadow sheltering her from the sun, but the area beneath her was very, very slightly darker than the rest of the sill.
Behind her sat the kitchen. A black wood stove sat in the center with a flat top big enough to use for cooking. An old iron skillet sat on its top. The skillet had been here when she'd arrived, and was in as poor a shape as most of the rest of the place. Years of build-up and neglect had worn away at the skillet. Seven patches of rust had developed inside, at least, that was seven she could individually discern. There might have been more, but she counted them as one, because they had grown into each other.
Tenderly, she had used a dash of oil and an old cloth, and with the heat of the stove beneath it, seasoned the rust away. It took several treatments, the rust spots getting a little less visible, and the cast iron's inner glow beginning to surface, but now it was perfection. Perhaps it didn't shine quite as bright as a new skillet would after seasoning, but it shined enough, and wore its age well.
-- [ end ] --
Example #3: Mary Loves to Bake
Lara couldn't help but smile. Mary was a marvel.
Everything was somewhere between chaos and perfection. Though ingredients for the cupcakes seemed to spill over everywhere, each splash of flour or misplaced egg looked like an accessory in her strawberries-and-cream-colored kitchen. Mary even fit the theme in her adorable apron, with the ruffled hems and colorful little dots of pastel pinks, blues, and yellows.
And if Mary wasn't talking, she was either humming or singing. Lara felt like she was sitting in the middle of a Disney movie, or some portion of the Disney world that existed off camera, and away from the action, like Mary's kitchen was her own little secret slice of Disney.
---- [ end ] ----
Briefly, about each piece.
The detail in the first piece works, because Horace is waiting for Duke Byron to arrive. He has never seen the study with his own eyes, and is therefore curious about the details. Taking the time to give the details also gives the reader a sense of the passage of time, that we are waiting with him; the longer it takes to read a description, the more time we feel has passed. That said, the descriptions never get into forced detail, such as whatever exact designs are in my mind. The reason for this is, readers will put their own stamp on it, and you can't stop them. Trying to express the minutest details in your brain can pull the reader out of the story, by forcing them to try and see exactly what you're describing, which may force them to alter how they've been imagining things to that point. And writing isn't about forcing someone to accept your vision exactly as you had it, it's about sharing an idea, or feeling, or world, and the descriptions need to facilitate that. That requires putting ego aside, and the story first.
In the second piece, we never found out what makes Sarah a witch. Because we decided detailing the clouds, the windowsill, the ladybug, and the kitchen were more important than remembering there was a point to Sarah's existence. Suuuuure, it established she lives in a rustic little cottage on her own, and spends time in her own thoughts, but that can be illustrated without diverting so much attention from the narrative. Detail for the sake of detail is harmful to the narrative, and should be trimmed or cut, or worked around elements that serve the story, such as in the first example, where each detail told us different things about Duke Byron, all of them serving to paint a whole picture.
In the last example, the details are as scant as possible. This is a sketch. The reader can decide for themselves what a "strawberries-and-cream" kitchen is, and fill in all the details they feel make a cheerful environment. This is because the details of the kitchen don't matter. The kitchen isn't the story. The baking isn't even the story. Mary is the story, and Lara is what facilitates that story. The kitchen is just the setting, not a character. The kitchen gives context, and lets us see more about Mary, but the kitchen isn't important (at least not to anyone but Mary). So, decide if you've turned the subject of your descriptions into its own character when you shouldn't have. Decide if you've spent too much time detailing things that aren't the focus. Decide if you've wandered away from the narrative for the sake of sharing description and detail, because it's so beautiful in your mind's eye. Decide if the details you've included serve the story, the characters, the pacing, and anything that doesn't is subject to removal.