there are quite a few hikes you could do. pick any one of the canyons that heads north from the river, and start hiking!
I've gone up panther a short ways, madera 5 or 6 miles, and fresno all the way to the solitario. it's possible to hike up one canyon, move to another cross-country like on the Rancherias, then down another canyon. water isn't going to be a problem in Fresno or Panther canyon, Madera canyon only had a few small springs, but they might be flowing well right now.
here's a map of a hike i tried. didn't get very far with a dog in tow, but i want to get back and finish it sometime.
http://www.grbphotography.net/bbcfiles/febranch.jpgPanther canyon has a few large boulders that require a bit of scrambling, and it would be easier going down that coming up.
the lower, narrow section of madera has a large 30ft pouroff that is very difficult to get up, as well as a few tinajas, so you have to get around it on the rim. it's worth going down in to look around though
Fresno canyon is the easiest to navigate, since it's the least "canyon-like".
i just picked up a topo, looked for canyons that looked interesting, worked out a loop/route, and went for it

look on my site for pictures of these places
http://www.grbphotography.net