Nothing for Nothing, Jerry, but, assuming you are using Detroit, I looked at Matrix for August dates and you can fly into Cancun for as low as 430 PP on Spirit non stop. Heck Delta I saw a non stop for 540.
So
Spirit 860
Private Van to Playa 50
Ferry X2 28
Room at $40x7 280
Mayair CZM to CUN x2 100
659 Per person = 300 MORE of Margaritas.
3.5 on the plane each way, 50 in the van, 55 on the ferry for a total of less than 5.5 vs 7-8 hours flight and waiting going down.
On the way back, say 15 minutes on Mayair, maybe a couple hours in Cun depending on which Mayair you have to take and then 3.5 on the plane home = maybe 6 at the most vs 8-9 flying out of CZM
Note:
Coming down:
The van will stop for beer at the Oxxo and you can finish the 6 pack on the ferry.
If you have to wait on the next ferry, the view and food at Senor Frogs beat the #$%^ out of anything in the Houston or Dallas airports.
Going back:
Arrive at CZM 30 minutes before the Mayair flight is plenty of time. Email for the best ticket price.
Just some ideas for you. If you are a real skin flint you could change the private van to the bus which is easy for like 8 pp. Or even bus and ferry back. We use Cancun and I like the ferry down as it is fun and I like the Mayair back as it is QUICK.