I do suggest a 2-night stay in Anaheim, though, even for a 1-day Disneyland trip. Otherwise you're going to be stressed out either in the morning or the evening, having to worry about storing luggage, etc. With two nights you can get there and get settled in, the next day enjoy Disney, and have one more night after that before moving elsewhere.

Do your research on Disney, too. One day runs the risk of being a huge stressor and disappointment without some investigation and planning.