We went to a nudist camp that's swinger friendly over Memorial Day weekend, and it was a blast! We both love camping, and for us, it was the best of both worlds.
I'm not sure what camp you are going to- but I'll answer based on my limited experience. I'm also going to make the assumption that it is a nudist camp.
What to wear- during the day, most women walked around wearing a small wrap of some sort around their waists. Alot of folks walked around bare naked, but that takes a little getting used to. For your first time out, take a little wrap. If you get comfortable, you can always take it off.
For the parties, I have found that I have alot more fun if I get into the theme. Keep in mind that it is a sexualized version of said theme!
If you enjoy watching and chatting outside of the mayhem, that's fine. No one will drag you, kicking and screaming, out into the middle of things.
If you want to join in, that's great, and if you don't, that's great too!
Personal hygiene suggestions: It is considered common courtesy to carry a small towel to sit on if you are nude.
Also, at the camp we went to anyway, when there was a group gathering- such as a pot luck dinner, people wore clothing. Shorts and tops (though alot of the women went topless), sun dresses, etc. Sarongs and wraps seemed to be very popular.
Bug spray. I get skeeter bites on my ass for NO man. (Or woman )
There's a bug spray out there that smells good. It might be Cutter. Comes in a pump bottle versus a spray... I'll check with the Mister and see if he remembers what brand it is.
Camp orgy?? Don't know, never been part of that! (yet)
I'd assume it would be the basic swinger etiquette. Be respectful of others. Don't just join in without asking. I think I'd hang back a bit, and watch what others do.
Do whatever it is that makes YOU comfortable. You and your spouse are number one priority. Trust me, you won't be the only "watcher." And you may surprise yourself by WANTING to join in!
Hope I helped, and if I can answer any other questions for you, just let me know! Have fun, I wish we were going!!