Magic Mountain 

Descent beta for routes in vicinity of Community Pillar: one 70 works perfectly on the raps, the first tree you see with slings at head height is an easy no-hands walkdown, head towards the Magic Triangle, don't bother with the rappel. The next tree is at the top of the Triangle gully proper, and is pretty short-50' or so off of small trees linked with a lot of cord and extended pretty far towards the lip. There's an interesting looking hole in the ledge not far down this rap-don't use this unless you brought 2 ropes. With a single, touch down beside the hole and walk climber's right to a slung boulder/nut anchor. A full rope rap puts you 25' above another tree, a solid scrub oak. I replaced the bleached slings on this one with a new dyneema. Another full length single rap leads to scrambling down the easternmost side of the gully to the final rap tree. On this rap, even with a 70, you'll come up 8 feet short. Aim slightly right to an easy varnished corner that is fine to downclimb at 5.3 or so. This lands you 20' from the base of Small Purchase.

There are 2 other descents detailed in Larry's Red Rock Odyssey: the (2 ropes required) Edge of the Sun rap route, which places you pretty far from your packs and involves a bit of hiking to return to the route base. The last is down the Crabby Appleton gully, which I would only choose as a last resort, if my rope was destroyed. The gully itself is an interesting hike, but trying to get down the thing quickly and safely without having been up the thing beforehand would involve leaving gear and possibly some "creative" rappels. Rapping off slings buried under small cairns HAS happened to people up there, don't be that guy.