You can start from wherever you want, but if you camp in the Enchantments, you need a permit. I figure if you've got so many days, you might as well camp out and soak it all up. The rangers are bound to run into you if you're up there for X days in a tent.
For day trips to the Enchantments, you just need to fill out a permit, but there's no limit or fee, if I remember correctly.