My 2 year old DD's favorites rides are small world, dumbo, carousel, peter pan, tea cups and buzz at DL and monster's inc, TSM, playhouse disney, casey junior, train around the park and bug's land at DCA.
My almost 5 year old son's favorites are all my daughter's favorites plus roller coaster in toon town, play area in toon town, jungle cruise, autopia, star tours, tom sawyer's island, nemo, boats in fantasy land, monorail and sometimes Pirates. He isn't a fan of the dark rides. At DCA he also likes my daughter's favorites plus soarin and the play areas. Favorite thing though is the water fountains in bug land! We usually spend a couple hours there if the weather is nice!
Older kids can also do matterhorn, thunder mountain, splash, haunted mansion (2 year old too), maybe space mountain for the oldest. There are some other rides in fantasy land too. I think I'm missing some others but have definitely hit our favorites!
Definitely do Goofy's Kitchen for a character meal.
For us, the best plan is getting to the parks at opening and hitting our hotel after lunch when the crowds get bad. We might swim or just hang out for an hour or two and then head back. I think more than anything, I feel refreshed and not grouchy by late afternoon. If you don't want to rest, having a nice sit down meal at lunch also works well for me! I think the biggest thing is not pushing the kids too much and enjoying it!