Need Multiple Entrances For This Room I'm Constructing. How Should I Approach This??

Im thinking of having two or three entrances so i can work on the plants from outside this room(so i dont have to sacrifice flower/veg space for walk space). Here's some photos of the 6x6 room im building. So far i just have the walls up:

http://imgur.com/a/kAlYL

I'm thinking of lining the interior with Foam Insulation board with reflective surface showing. And maybe using plywood for exterior siding? I'm really still undecided on material any suggestions are more than welcome. How should I cut out my entrances though? Should I use slabs of plywood on hinges as doors? Is there a sliding mechanism i can cheaply incorporate? Make detachable walls? Velcro? Zipper? I'm not much of a builder and dont have experience with a grow yet so im not quite sure what my best options are. Any feedback will be greatly appreciated! Thanks in advance

As more door per "object" is practical you need to figure out a system of doors so it is lightproof.

If you will be going "in" every day don't do something complicated (i believe it's hard to lightproof detachable walls)

I mostly use DRY walling for building smaller rooms (wood prices are higher here than drywall)

If you go indoor room door type you will need to light prof it a little (the bottom side usually doesn't have anything)

And one more "hint" but it looks you already built your room/tent - always build according to planed light and try to hit 800-1200 PPFD.

Double doors are usually a one and done. You dont need three of tjem. Centralize and save a buck.