I would start by browsing the menus at
www.allearsnet.com to see what your family might enjoy and what your budget allows. They are broken down my park. Then, you can come search for reviews on the restaurants that looked appealing, or post a thread and ask.
I can tell you my faves at each park:
Epcot: counter, just about anything in World Showcase but Mexico (think a step down from Taco Bell). table service: Marrakesh in Morocco
Magic Kingdom: counter: don't really have one. Table: CRT for dinner. We usually hit a resort for dinner there - like jump on the monorail to Poly for Ohanas - YUM!
AK: no faves, never eaten there. They only have one table service and it's RFC and I don't care for RFC's anywhere. The counters is supposed to be pretty good.
MGM: counter: none, they all stink

table: really really love Brown Derby, but 50's PT is great too. Sci Fi is great for the atmosphere
I think most of the great food is at the resorts, too, so you can see which resort restaurants you might want to try as a break from the parks, esp if you are already taking a break mid-day.
Also, since you've missed the 90 days out, you might have a hard time getting AR's for the hottest spots, so be sure and write down backup restaurants in case you can't get into certain ones.
I'd narrow them down and call ASAP to ensure you can get in someplace =) Good luck and have fun browsing the menus!