I have been to SW, the Space Center, AK, and Universal.
The last time I was at Universal we drove up from WDW area, and walked in on EVERYTHING. It was in June. IOA was not open back then, it was a Saturday and still the park was empty. We did all the rides, saw one show, got asked to do a consumer survey, and still got it all done in less than 6 hours. FOTL would be a benefit if the parks are crowded.
Sea World, I can spend the entire day there, I love the Behind the Scenes Tour, but if you are only going for a day, you may want to not do a tour and just stick to the shows and attractions. I was there in August of 03, got there at just after opening and left about 3:30 pm. Did most of the thrill rides, maybe all of them, saw Shamu, saw the sea lions, saw the polar bears, and saw one inside show. Unless the park is crowded, it is easy to do it all in a day. They offer meals with Shamu, but for the price of admission and food, I prefer to see the show and eat somewhere less costly.
Space Center, wow it had been since 1987. I lived in the DC area for 32 years and went to the Air and Space Museum a lot, so for me the space center was meh. Some rockets on display, some space stuff and we saw a mock up of the control center. The best part was taking the bus tour of the outer areas, the Vehicle Assembly Building, the tracks that the rockets are lushed on to get to the launch pad, and we got semi close to one launch pad. I imagine that it has change since then, but it was a 4 hour tour in total. Remember it is about 90 minutes from Orlando to drive.
AK I love. I love the rides, I love the shows and I LOVE the animals. I have been on the Safari about 10 times, sometimes you see little to nothing, but I have been close enough to touch a Rhino and a giraffe. The ride is semi hokey after the first time, but if you tune out the script, and concentrate on the animals, it is really great. And there are 2 walking trails, one with gorillas, meerkats, and birds, the other with the tigers. A lot of people complain about the heat in the park, it does tend to be a bit more humid as there are a lot more trees and more narrow paths. But I can easily spend a full day there.
I can't tell you how to plan because everyone has their own ideas of what they really want to see. I think you have picked a great time to go weather wise, the Flower and Garden Festival will be happening at Epcot so the AK may be even less crowded.
Have a great trip, I will tell Mickey to expect you when I see him next week.
I actually just renewed my AP... and it was only $99 for the full year for the renewal.. YOu can't beat that with a stick!! LOL!! Whichever hotel you stay at RPR or PBH.. you will be happy.. they are both fabulous... and RPR is actually a bit closer (walking distance) to the parks.. especially IOA... and right down the road from Margaritaville!! 
