The place in Coggan is for men only it appears. If I can remember their name I'll get back to you. Check the Groups by searching Iowa and there is a discussion in there. The former Camelot group in Des Moines does still have some events in the summer and occasional house party. There is also a small private campground near Indianola. I can tell you of many spots where you can get some hiking, biking or river sun. PM me.
One of my favorites is biking naked. There are many rail trails in IA where this is possible, sometimes for many miles at a time. Know the section you want to ride, we ride with a pair of shorts and tshirt on the handlebars. Since you can usually see 1/2 mi ahead, you will have time to get off to the side and get dressed but this has only happened a couple of times in a few hundred rides. If you access the county park guide you will find several parks and trails you didn't know about. One of my favorite biking trail isn't even on the map cause it is undeveloped, with rough gravel but this ensures very little traffic. Some of the rail trails provide good access to streams where you can hike just out of sight from a bridge and layout on a sandbar or play in the water naked.