From another "CAH Kid’s" point of view:

Most of the time, the last thing we (those of us that have CAH) want is yet another reminder of our "problem" or how we’re different.  I think, if it were me, I’d loathe going to a place meant to fix me...

A regular sleep-away camp that focuses on being active/playing sports might be good enough.  I know the ONLY way I can maintain my healthy weight is to be active for at least 30mins a day (breaking a sweat). I can’t even describe the tremendous effect it has on my mood as well as curbing my (voracious) appetite.  Of curse my dose of prednisone has to be right too.  (In the last 18 mos I’ve gone from 12.5mg/day to 4.5mg/day and it has made a HUGE difference.)

A lot of families find that their kids lose weight at sleep away camp (not necessarily "fat camp"),because the kids are constantly active and the schedules are fairly tight. It’s also a really great opportunity to meet new people and mature a little bit.