At other parks I carry a 6"x9" bag. Just enough for all our wallets, phones, sunscreen clip on, cooling towel ties on the side, 3 cheap ponchos, ziplocs, pressed penny book, and coins. It's easier for us to throw it all in the same bag one the way, I go through bag check, while DH goes through no bag line with DD9. No one has to juggle putting everything back in pockets at the security exit. Disney is the only place I go with a small backpack IF DD9 wants to have an autograph book.