4:00 flight gets you picked up between 12:45 and 1:15. You need to be at the DME bus stop, ready to go, at least 15-20 mins prior to your stated pick up time.
That puts you at the bus stop between 12:30-1:00. You will probably need to stop at Luggage Assistence for your carry on bags.....that could take up to 20 mins. Add bathroom stops and that last walk through the gift shop....another 30 mins. You need to be at the resort by 11:30. Probably better to just hang at the resort. The only way I would go to a park would be if it was an EMH morning. But you would have to be leaving the park by 10:45 at the latest.