I depends if you are using a TA or booking it yourself. If you are DIY, then once you've decided on your dates I would book the hotel as soon as your dates comes available with the hotel of your choice. Then start hunting for cheap airfare. Since you are travelling during Spring break, you would need to book it further out than other times of the year. I think 6 months out would be fine. The longer you wait to book after this time frame, especially after the 4 month mark you will find it much harder to find the hotel you want to stay at. I would love to stay at one of the Disney hotels, but can never justify the expense of it. However that being said it's worth doing once, just to experience it. I personally like the Best Western Park Place Inn, for it close proximity to the parks, and it's a good, clean, basic hotel with excellent staff. I can also recommend HOJO's as well. Hope this helps.