I think that's way too close. Flrst, you're assuming that your flight will arrive on time. Even if it does, it'll take you at least an hour to get to your resort (3:10). The shortest possible trip on DME is about 30 minutes, and you have to figure in time to get from your gate to their boarding area. And, a bus may not be sitting there waiting when you arrive, and even after you board, you may wait awhile for other passengers.
Then, when you get to the resort, you need to check in. And then, catch a bus to MK, and get a monorail or boat to GF. I'd figure another hour, at least, for all of that.
All of the above is best-case scenario. I'd move the ADR to another day.