You can do it in four days, you need to plan on getting up early if you are going to shuttle from hotel to park. Buses can take some time. Yes actually character meals are basically a meal (b/l/d) buffet or family style. And as you eat your food the characters go from table to table singing autographs taking pictures and mingling at each table. Its a very popular choice to eating, especially with younger ones. A reservation is recommended especially for breakfast ones, but not always recommended. Some of the best ones are:
Crystal Palace: Magic kingdom, it has breakfast, lunch, and dinner. I think you have to have a reservation (or priority seating as its called) to have the breakfast one. It features Winnie the Pooh characters. Its buffet style.
Cinderellas royal table(i think its called that): Magic kingdom. Breakfast. RESERVATION IS REQUIRED!!! This is the most sought out character breakfast. It has princess characters, and non princess (marry poppoins). Great for the little princess in your family. Everyone is served the same dish. Eggs bacon etc..
Princess breakfast in Norway in Epcot

sorry don't know the name.) EPCOT. Reservations are required. Buffet style with princesses.
Garden grill: Epcot. Dinner with Mickey and pals. L/D. Family style, which means its like thanksgiving. Turkey, catfish, mac and cheese. I think kids can get a different set off food but i cant remember.
Liberty Tree: Magic kingdom. L/D. Dinner with mickey and pals in colonial era cloth. Same as garden grill in food style.
These are the major ones at the park. Most are reasonable priced. About 20-30 a person. Like i said earlier priority seating isn't required for some but is really recommended. You can call up to 90 days in advance for seating. None of them really fill up except Cinderella table which is in Cinderella's castle. When i went as a kid, it took my family three trips to get a seat here. So yeah any more info just ask.
