If you go on an early entry day, you could get into AK at 8 am. Keep in mind though I'm a commando, and I find spending 13 hours in the parks thrilling.
It's not ideal, but my kids would rather spend 1/2 day in those 2 parks and 2 whole days at MK. In October we got to the gates at 9, did the safari, Pangani and the other trail, Conservation Station, Kali (twice), Boneyard, Dinosaur, Triceratops Spin and that new ride in AK. We wanted to see the Lion King and Tarzan, but it was very crowded and too hard to zigzag around the park to try to be somewhere at a set time. We left around 2 and were at Epcot by 3. You may have trouble w/Mission Space and Test Track if the fastpasses are already given out for the day. That happened to us, so DD7 and DH used the standby line for those two while I took DD3 to the Living Seas and the Fitness Fairground. Then Test Track broke down and threw our schedule way off. It was 6 pm by then so we skipped TT. Ended up going to Downtown Disneyto play with Legos, but my plan was to spend 6-9 in World Showcase.
Sorry this got long. We're going back next month and I'm working out our plans. You'd think it'd be simple....just do what we didn't get to do in October, but we always end up doing our favorites each trip.