If it were me, I'd spring for hoppers. I love being able to make the decision to hop to another park whenever the mood strikes. And with the new express buses for those with hoppers, it's even more appealing.
I'd also suggest that with no plane to catch, you can sleep in and still be checked out of your room on time AND have a nice breakfast before heading out, which would free up that third park day's morning.
I'd do the following:
1. Arrival day - stay at resort
2. Park in AM (I'd choose MK here); afternoon rest; Another park PM*
3. Park in AM; afternoon rest; Another park PM*
4. Park in Am: afternoon rest: Another park PM (I'd choose MK here as well)
5. Departure day - sleep in, check out of room, have a nice breakfast, head home
*I'd make sure one of these PM parks is Epcot for dinner and IllumiNations. The other PM park would depend on which nighttime entertainment you're most interested in.
Where are you staying?
We are staying at Asmu. We are planning on doing Illuminations on our anniversary and the MK new fireworks show.