The joint trail is superb. Definitly work hiking through. So far as water, I'm guessing that you will be doing a lot of water hauling no matter your route.
Finally, know matter how well intentioned the recomendation, driving the elephant hill/silver stairs just isn't worth it unless you like to kick the shit out of your truck. (and if you do, it's a friggin' blast!)
There's also some nice river side / roadside camping in lochhart basin.
Have fun, it's beautiful!