I like the banner idea!!
also, you could see if a local store would let you use a firepit, throw some real firewood in it, and use white Christmas lights wrapped in orange/red/white tissue paper to make flames. I made a "firepit" for a photography prop for a friend using white lites and red and gold Christmas tinsel that reflected the light and it worked really well also.
Camping chairs around the "campfire" for a reading area.
the banners on the front of their desk might be fun to....as Kelly said, you can incorporate their name and the insects at will.
lanterns hung from the lights might be fun
I'm trying to think of something with log cabins.......you might email all your friends and see if anyone has an electric fireplace...you could make the classroom into a log cabin??
I always think of fishing when we go camping also. Maybe have a "pond" with small prizes of some kind. Figure out something that would allow them to "go fishing" for a prize. You could put a little bucket on the end of a fishing pole and put all the prizes behind a screen of somekind. Give them "bait" for things done well or good deeds and once a week, the kids can trade in their "bait" (paper worms or minnows or something) for a prize. It can be something as simple as pencils, fun erasers, etc etc. My kids used to earn some kind of bonus bucks and they could "buy" gifts once a week. Maybe different types of bait give them different prizes. Worms are the simple things, minnows give them bigger prizes??? Or maybe if they save up say 10 worms, they can go "deep sea" fishing for a bigger prize yet? There is a lot you can do with that one!
that's all I got now....let me think some more.