+1 on the ^rack. Thinking about getting one myself.

Depending on just how big your backpack is, a milk crate may or may not work. But if you can snag one of those flat crates used by vending machine companies, that would increase the overall area of the main deck. I remember a BF member posting a pic of carrying home a pumpkin on a flat Coke crate. I would try and search for it, but ya know....