If they can make the little one in a crib till he/she's 3 plus, that would be ideal. We took my little guy (third child) when he was 3- we paid for park admission, obviously, but I told the hotel that he still slept in a crib so they sent one up. He wouldnt sleep in it so we had the boys sleep w/ Dad in one bed and me w/ my daughter in the other bed- worked out fine.
Otherwise, go w/ Port Orleans w/a rollaway for a budget or two rooms at an allstars (in off season you can do that for like 100/night and the extra bathroom is a great bonus)