One night is enough to stay in the Disneyland Hotel. When you arrive in the first day, you could go to disneyland directly, spend one night here so you could visit the park once more in the second day for free. In the second afternoon, you could chek-in a hotel in the downtown area, and then do some visit leisurly and tasty the local food. In the last two days, you could visit some other places as you like. I think you have enough time to see this city!