So, you check in on May 22, head to MK early on the 23rd...your checkout day. You are basically fine until midnight on the 23rd. But, since you'll be returning to the resort around 6 am, technically, you aren't entitled to ride DME....that option ran out 6-7 hours prior. But.....check at the front desk when you check in....there may very well be something they can do to help you. If not...I would book the Mears shuttle....$20 one way back to MCO. Then, you may very well just be put on the DME bus in any case.