B.C.
Dude, I'd just get a regular backpack. That's what I use. We got one for $3.99 at Walgreens and it's great.
For the regular stuff, (diapers, pull-ups, extra clothes, snacks, and her blankie) we use the backpack. For overnights, I just toss her stuffies and quilt in a large tote and we're good to go!