When I make my personal plan for any of the parks I get there before opening and do some of the attractions that are NOT air conditioned first. I should also mention that I never get in a hurry during my solo visits to WDW.
In the Animal Kingdom (which always seems to me to be hotter than the other parks, but I don't know why), I walk back to the African section, get a fast pass for the Safari ride, walk the nature trail nearby - taking my good old time, then ride the Safari, stroll down to see the Lion King Show which is air conditioned, walk to the pizza eatery and sit inside in the AC while having my pizza and drinking my beer, finish my beverage while walking and waiting in line to see the 3-D bug show which is air conditioned, stroll over to EE and ride the coaster a couple of times using the single rider line, and, if I'm really hot by then I'll do the river rapids ride and get soaked. Then I usually head for the resort, sometimes taking time to ride the air conditioned dinosaur attraction if I'm in the mood.
The real trick to all this, if there is one, is (1) taking my time, (2) not rushing around, and (3) having a realistic plan that includes air conditioning, with a minimum of backtracking.
As you can see below, my next trip to WDW will be during the non-hot part of the Florida year. But I'll still use a plan that makes it easy on me, and includes the things I like to do and see.
Enjoy.