Most dealers there can accept credit cards, but the 
small ones cannot.  However, a few small dealers may
able to ask their next table' dealers to help out for the
credit card payment.  All in all, it's safer that you 
bring a lot of cash if you plan to buy a lot of stuffs.  On
the other hand, Disneyland Hotel has a lot of ATM machines,
so as long as you bring your ATM card, you'll be fine :)