I heartily second the motion of reading Fletcher & Rawlins' Complete Walker IV. I think there's even a piece in there called "A Sample Day in the Rain."

It's the only book on backpacking I've ever bought and kept after reading it. (I kept each of the first 3 versions until the next one came out, then passed them along to friends.)

Fletcher on backpacking is like Bruce Catton on the Civil War: there will always be newer, hipper writers, but there will never be a better writer on the subject.