Smithing isn't a high priority, and you can always come back to it. Enchanting takes all game unless you grind it, but that'll provide your endgame Armor with Robe enchantments. Block is optional, Alteration can give you the Atronach Perk, but you can't turn it off, so you better be damned sure you're not going to be conjuring after that, unless you want to pull a Legendary Loop on it. Also, Ebonyflesh can make up for not Smithing. Restoration would be nice, and the Ward Absorb Perk adds more Spell Absorbtion at will. The Recovery perks also enhance your Magicka Regen, so you won't need robes as much once you get to it, but both are canceled out by the Atronach Stone.
Try it all, see what you like. You can always restart, or go back to an older save if you end up nerfing your character. Work on Weapons, Armor, and Destruction first, save, then see what you can tack on the best. Block too, if you're going to use it, because it's a very slow leveler, and has to be built up throughout the game. (Without using exploits, like Grinding.)