Call Chase and check with them. I just read my card agreement and it says that payments will first be allocated to purchases with the lowest interest rate. Makes sense, charging interest is how Chase makes their money. However, I think this means that if I have a Disney vacation charge (at 0% interest) and other charges (gas, groceries, whatever- which carry a 12% interest rate), Chase will put whatever amount I pay towards the 0% stuff first and the 12% stuff after that. SO...If there is a $500 charge from a Disney vacation and a $1500 charge from groceries, gas, etc., and I make a $1500 payment, the money will be used to pay $500 towards the Disney vacation first and the remaining $1000 will go towards the rest of the charges, leaving me with a $500 balance that will be charged 12% interest!!!
I think that if you only use the Chase card for the Disney vacation you won't accrue interest...just don't charge ANYTHING ELSE on this account!!! I'd call Chase and double check.