next summer


Summer? Are you sure you want to do that? Temps can exceed 115 or more in the main canyon, and it does not cool off much at night.
November through April are the "temperate" months.

Our river permit is for June of '11, and we are planning for 100+ degrees every day.

for best months and temperatures,
http://www.grandcanyonhiker.com/plan...er/index.shtml has very good info.

On other notes, you might look into some of the info on such sites like Lightweight backpacker. http://www.backpacking.net/
While you don't need to go the way of fanatical ultralight backpacking, there are many good things you can do to get your baseweight down. Especially for women who are smaller, this is really important. Some of the internal frame packs out there ( you cite an Osprey) that you like, are really heavy just to do so many buckles, webbing straps, and other doodads built in. You might compare that to some of the gear made by Go-Lite, for example.
Boots is another area where the lightweight offerings are just amazing. Nothing like the solid leather pivettas and asolo's I strarted with years ago.