It's really busy right now because of Spring Break- I just got back today.
Everything in the Magic Kingdom will be very crowded. You'll want to phone ahead for Priority Seating if you're looking for a table service or buffet meal inside the MK. You'll probably find the character dining locations (Crystal Palace, Liberty Tree Tavern for dinner) the most crowded.
If you opt for counter service in the parks, I'd recommend hitting at a really off time to avoid the worst of the crowds.
You ask about eating at "all of the resorts"... if you can narrow down what resorts you mean, what park you want to be near, or what kind of dinner you're looking for (quick burger, or full service/gourmet) you'll probably get lots of good suggestions really quickly!
Mostly- know that it WILL be crowded. Priority seating arrangements and lots of patience and flexibility are my best recommendations for dealing with the packed conditions.
Have a great trip!