From the DIS Planning tab: Forms of payment
Cash (U.S. Currency)
Traveler's Checks (must be in U.S. Dollars) Photo ID required
Disney Dollars (Disney's own currency)
Credit Cards
Currency Exchange
Walt Disney World Gift Cards
Disney Visa Rewards Card
Why not just buy a Visa gift card or use your ATM debit card as a credit card? Travelers checks will require you to flash an ID and your change will be cash. If you are trying to minimize handling cash a card is a better option. Keep in mind you can buy gift cards in demoninations just like travelers cheques. I haven't used travelers cheques in over a decade.