If it comes to this, it'll be like being on the Amazing Race! But, being stuck in PdC is certainly preferable to being stuck anywhere in the states. I would assume some hotel will have a vacancy.
If you have time, maybe having a few PDC hotels in mind would help with plan C/D/E. PDC hotel map
Playa del Carmen, Mexico map with hotel locations
The ferry is the white line near the top of Box E.
The ADO bus station is at the northwest corner of Ave 5 and Juarez.
If you know all this already, ignore my rambling.
As for the Amazing Race, would you have gotten all the currency named totem poles at the end Sunday? I would not.