I went on a 30 mile backpacking trip with my scout troop, we tackled that in about 2 days, in the ozarks over in arkansas. I only took the clothes on my back, and washed them thoroughly every other day. (no soap, just a good soaking,wringing,rock thrashing, and cedar-beating) It kept them really clean, i had the cleanest best smelling clothes by the end of the trip (tehy actually smelled good, like cedar!) but the upside is i eliminated about 6 lbs.
allso, I should teach you how to make snares, you could skip packing food in alltogether!