Lots of places to dry camp and boondock in the Dixie and Fishlake National Forests. You can download the Motor Vehicle Use Maps (MVUM) at these links: Fishlake NF MVUM, Dixie NF MVUM and probably pickup printed copies at the multi-agency visitor center in Escalante. If you are not familiar with it, checkout the Fishlake Scenic Byway.
Posey Lake requires about 15 miles of gravel road with some steep sections...just so you're aware. The campground has approx. 20 sites and some are reservable. It closes the first week of Sept. Hope it works for you!
Been to Posy before, know all about it. Drive a TC, size no problem,we like remote.We like gravel roads, keeps the crowds down,we go to get away from people!!! Thanks to all.
Second Calf Creek, very nice place to visit. If you like scenic drives and don't mind a little graded county dirt in your TC, the Burr Trail/Notom loop is fantastic. The Hells Backbone route from Posey to Boulder and the start of the Burr trail would be a nice route.
A visit to Capitol Reef is always nice too.
If you like wildlife viewing and less crowded boondocking, leave Posey and head up on Griffin Top for a night. This time of year is excellent for seeing mule deer and elk in the meadows off the road up there around evening time - and it's a thousand times less crowded than Posey.
No shortage of indian rock art to be seen not far off the main routes too, if you are in to that sort of thing.
Tons more to see and do in the area, especially fishing. And Posey is just about the most crowded spot on the mountain, and not nearly the nicest either, if you don't mind a little dirt road, there are many, many nicer places to camp around there.
If the weather is cool, I'd recommend a hike to Calf Creek Falls:
Maybe folks swim in that pool during warmer weather -- I don't know, because we were there in April of 2006, when it was in the 40s. Great hiking weather.