There are a lot of general-interest naturist discussion groups, but that's not what you asked about. If it's specifically the outdoors you want, Netnude has a "Wilderness/canuding" section. (http://www.netnude.com/mb ) This board is very active and has a wide range of topics, and your stuff would probably fit: http://clothesfreeforums.com/eve The Naturist Society's Outdoor Recreation Interest Group has a discussion board on Yahoo: http://groups.yahoo.com/group/naturists-outdoors/ And there's always rec.nude, though it's a place where anarchy prevails.
clothesfree is good though only if you have the more conservative minded view of nudity. That seems to be the way its leaning and unless you agree with some of the people and what they say there then they might not be all that friendly to you. Just a word of warning. Thats why I come here and go to other more liberal nudist forums. I cant stand all the regulations and tongue and cheek kinda things you find on these big soft fluffy forums like clothesfree.
You quickly realize that naturists are a talkative bunch, and many of them all too likely to burst into flames. They'll march off each other's Internet boards in a huff or get kicked off, and then they start a new board and badmouth each other. Especially this one woman in Florida who's quarreled with just about everyone! The thing to be aware of from the beginning is that some nudists come from the tradition in "textile" society that says that if people, especially women, get naked it's perfectly logical to see it as a sexual situation, and then there are others who say that's exactly what naturism ought to be trying to avoid. So some of the naturists are constantly starting discussions on the Internet boards that involve sex in one way or another, and the rest are thinking that's a betrayal of the whole naturist concept, and it becomes a situation of the "sex obsessed" ones versus the "prudes". That conflict is at the root of a lot of the fights, so there's more to it than just "family type forums" being strict.
I guess naturism is really best with either just yourself and nature, or you, nature and close friends. I used to take trips out to the mountain rivers and other wilderness areas with my friends (mixed gender) in groups of up to 12. We all got naked (mostly because it was hot outside and we were swimming a lot) and all got along fine. We would share good laughs if any of the guys got erections and trusted each other with how we were feeling at any given moment. I guess things would be a lot different at a public nude beach or public forum.