You should forget it. (did you look at a Topo Map?)
Haven't done it yet... but it was asked and answered here:
http://yosemitenews.info/forum/read.php?3,56631,56631#msg-56631In my defense... I have done Muir Gorge since then.
Seriously though... don't even think of going down that-a-way... unless you know
for certain you can x the river. I've come up with a few other ways down...
have yet to do any of them tho... maybe this year... maybe not... too much to do.
Have fun... dunno ur route... but lots of trails... I'd rec. doing those first.