In DCA, we like the San Fransokyo area (Lucky Fortune Cookery, Aunt Cass bread bowls and the birria tacos at Cocina Cucamonga) Personally, I don't care for the food at Flo's or Crazy Cone, but my kids love it. We like GCH Craftsman Bar & Grill as a breather to get away from the crowds.
In DL, Rancho del Zolcalo and Bengal BBQ are popular. We also like Tiana's Palace and Cafe Orleans. I think the begniets at the Jazz Kitchen in DTD are much better than the ones in the park.
What dates/season will you be going? Disney's California resorts often have seasonal specialties.