Awesome trip!! And a great way to end it. Yes, you get the most done early in the morning at DL. The first couple hours are always the best for us so take advantage of EMH! You will have it at DCA or DL each day. In DL Fantasyland & Tomorrowland are open, in DCA Cars Land, Soarin, Screamin', TSMM are the highlights open. It's easy to get a lot done in a short amount of time without pushing yourself because of how close everything is compared to DL.
Do be ready for the parks to be crowded. Kids are still out of school. And you will be there over a Fri-Sat I see, and parks are more crowded on weekends. Benefit will be long park hours and more shows. Also the earlier EMH, the fewer people show up! We found 7am to be our favorite EMH- well on the mornings we could get the crew out of bed early enough!
Would 5 day tickets work in your plan? If you arrive late at night and depart early in the morning I can see sticking with 4 but I ask because personally our sweet spot is a 4 night stay & 5 day hoppers. We arrive around lunch and hit the parks a little before returning for a pool break and go back and do a lot that first night. On departure day we stay in the parks through an early lunch (you get EMH on departure day FYI). It was like $15/ticket I think to upgrade to 5 days from 4 and it was very much worth it for our family.
It sounds like you have quite the amazing summer planned, have a wonderful time!
