While it will be crowded, there are ways to get around the crowds. Eating at off times is your best bet. Disney is designed to accomodate thousands of guests at once and you'll be so used to standing in line to ride rides that time spent standing in line to buy food will just seem to fly by. Unless you just really want a break from the park, I wouldn't spend the time traveling back and forth to your hotel just to eat lunch. You'll be just fine. I would check out
www.allears.net to see which QS places you might like to try in advance so you'll have an idea of which places offer the foods you like the most. You can NEVER be overprepared for a trip to the World!