When I need some pelt fast for smithing, or just for some lucrative hunting, I hike from Whiterun across the tundra toward Bloated Man's Grotto, kill everything that yields pelts on the way, kill everything in the grotto, then head toward Rorikstead (note there's a little pool just off-road, past a bend in the road, as you travel west from the grotto that usually has three deer/elk grazing around it, so sneak up on them or they'll spot you clanking your badass armored way down the road and dash up into the rocks).
I kill whatever I come across en route to Rorikstead too. If I haven't been out hunting in that area or have cleared the grotto recently, I can easily come home with a couple bear pelt, a couple or more sabercat pelts, a half dozen wolf pelts, a half dozen fox pelts and 12 or so deer/elk pelts. Then I use those pelt to make a bunch of leather armor.
Party time Skyrim-style!
The Rift around Iversted has a lot of bears too. Pinepeak Cavern, which has one bear guarding outside and one inside, is on the other side of the bridge and to the right as you head up to High Hrothgar. If you head out of Ivarstead the other way heading southward, off to the right side of the road and into the trees there's Honeystrand Cave that has a bear guarding outside, plus a beehive and bees, and two bears inside. Both caves have the added bonus of having some loot inside. There will be more bears around the Rift past Honeystrand so just wander around and follow the sound of bears grunting and growling.