Dude, I have the SAME exact backpack and MREs! I always keep that backpack in my car for spur of the moment beach runs (spare clothes, sun block, snacks and water) and I've been meaning the throw in some MREs.
On top of a chicken crate I use for a locker to keep all my books in, an overnight bag (enough clothes for a weekend, toiletries, extra sandals), extra wax and a leash for the boards, spare towel, Wet-Ones, 5 pairs of shades, umbrella, multivitamins, Gatorade, scissors, jumper cables, bungees, flashlight and always some magazines. I've been pretty much sticking to the pavement and not going out, so I cut the junk down in the trunk. I used to keep a whole bunch more, but it got in the way of school stuff so I had to cut it out.
That's all amatuer compared to you arsenal though! Looks like you could go for a week lost out in a canyon, and still be a happy camper.
