I went on this Outward Bound trip in 1992. I still have the receipt, $995 plus airfare to Vernal, Utah. Now it's $1495. Seems reasonable.
If you have never been on an Outward Bound trip but you are considering it, I recommend Outward Bound wholeheartedly. Yes, you will have to crap into an Army surplus ammo can (they call it "The Groover"), and you will have to take turns cooking and cleaning up. You will be responsible at least once for emptying The Groover. But they supply everything except the clothes you want to wear. They even provide the sleeping bag. All travelers receive a disposable "fart sack" that lines the sleeping bag you are issued. Potty humor is common on Outward Bound trips.
The guides are top notch. The food is good and after a few days in the Utah canyonlands with no facilities you will learn to really love "cowboy coffee," complete with grinds floating on the top in your mug. For the 18+ trips, ages ranged from mid-20s to mid-50s. I think that anyone in good physical shape can handle the raft trips regardless of age. Just be prepared for no tents and no air mattress. If it rains you sleep under the raft.
Sleeping in a remote desert canyon in the open air with no tent... it doesn't get much better. If you think that's weird, I suggest you try it.