I wouldn't do that much down time/ resort time, but I know everyone enjoys different things. The one thing that jumped out to me was the late morning Epcot arrival, then leaving after lunch, then going back for the evening fireworks. I think I'd try to bring or rent a stroller (city mini with big shade) so the 4 year old can chill out/ rest in that, and just stay at Epcot for the day if you are arriving late. You'll hardly see Epcot otherwise. Walking around the countries is really enjoyable for the kids when you get different snacks, play Agent P, and buy the passports so they can visit the Kidcot stations and get their stamps. Don't miss the desserts at Les Halles! We got a tray of a whole bunch of desserts - then cut them, sampled, and voted on our favorites. It was fun and they were all so good.