My goal is to pay for as much in advance as is possible either thru rewards programs or thru direct purchase/payments.
So far I have already paid for all my park passes. I also have enough frequent flier miles to get 4 free flights. A rewards credit card's points will pay for the rental car.
I have been purchasing $DD every month in an effort to prepay for the meals we will eat onsitean any souvenirs. Every purchase goes on a rewards credit card in order to get a little kickback. I really don't like carrying so much around in $DD, so I'll probably have them put it on my room account when we check in and then use our room key to "charge" all purchases back to that account.
I will put my room deposit on my rewards credit card when I make my reservation and then pay off the balance using the same card when we check in. The $$ to cover the cost of the room is already sitting in my little WDW Savings Account. DH will not tolerate any type of debt, so the $$ has to be there ahead of time or else we don't go.
Naturally, we will have some cash on hand for the little things (tips, small purchases, arcades, airport snacks, etc) and we will both be carrying credit cards witha zero balance with us in case of an emergencies.