Yeah, I don't know that I'd try going
up Rattlesnake Canyon again any time soon. It was pretty fun right until I took my tumble, and then it was no fun at all to limp back down! I am terrible with heights but I'm also like a cat - I go up easy but coming down is a struggle. Still, Rattlesnake definitely fits into the "better down than up" category.
I do have a GPS and always carry it with me - often for route finding but sometimes just so I can admire my track in Google Earth afterwards and wonder why I have a talent for picking the dumb way up.

A GPS track would be really helpful.
Carey's Castle is on my list ... I'm actually working on a plan to head down to JT and Anza-Borrego later this month and Carey's Castle is one of the planned trips. I live north of JT so I often explore up there instead of down south. There are some really neat things down south that I need to dig into.
I took a look at David Harris' description and pulled up Google Satellite View next to it. I think I see what he speaks of, though the distance measurement from Willow Hole doesn't
quite line up. ( This is how most of my adventures start: "Eh, doesn't quite match, but good enough! Let's go see!" Eight hours later: "Man, this was a terrible idea. Lots of type 2 fun, but I really need to start planning better." A few weeks later: "Ah, how bad can it be? I'm sure it will be obvious when I get there!" Slow learner, in other words. )