Wal-Mart on Ambassador has a copy on the front shelf with the MTG and other card games. The box looks to be in decent shape, but there's only the one.
Amazon Prime will get you a copy of Munchkin Pathfinder Deluxe here tomorrow for $27.22 (shipped 1-day shipping $22.23 + 4.99 S&H). It's the same board and accessories with different graphical themes and a different base game deck.
I usually stay at one of the hotels just outside of the park, (usually Castle Inn & Suites). I don't tend to come back to the hotel during the day unless there's an emergency, so I'm in the park from opening to roughly the closing of Downtown Disney.
My day pack generally includes:
I know that sounds like a hell of a lot to bring into the park and carry around, but honestly it all breaks down to fit into something like this with room to spare and it's fairly light. Well, everything but the jacket fits in the backpack.