I want to play an avoid the main quest. How can I do this. I basically want to leave Helgen with nothing. I want no enchanting, basically whatever my character finds is what he uses. I will not be using perks, maybe I'll choose 2 perk trees and that's it. Mainly I want to play as an undragon born.
Same as in Oblivion you could just ignore the quest entry and don't visit the person that continued the main quest. This way the world didn't have any oblivion portals in it, and you could just play all the way through the warriors guild, side-quests, etc...
Here just do the same... exit Helgen and be free. Ignore the quest about visiting whoever they tell you.
Anyway, I don't understand your point about "not use perks, don't want enchanting", etc... There is no need for any of those skills here... with my char (I'm playing a dragonborn, doing the main quest, etc.) I just use the only combat skill I choose, wear the armor type I chose, and use 3-4 more skills that fit my template. Even if I want that cool heavy armor because it looks good, I don't use it simply because my char "can't". It's light armored (you know,
"light on your feet, smart"

). I pick perks for those 4-5 skills, and that's all. I didn't want a crafter so I don't do smith, alchemy, enchanting, or whatever... same with Magic. It's an archer, so I don't read any books neither use any spells, of any type, even if I would love to. That's why I will create a Mage later.
In any case, have fun!