Did I see you can do a direct, non-stop from Boston to Cancun on Jet Blue?
Yes, you did see that. It's 4 hours and 15 minutes, too. It's even a fairly reasonable price if you get tickets right after they go on sale.
Saturdays only, though.
That's how we're going in September. They keep moving our departure times from each end earlier and earlier. Originally, we were leaving Boston at 1140 AM and Cancun at 1555 PM, which is eminently reasonable. No pre-dawn schleps down to Beantown, etc. Now, they're 0850 from Boston and 1435 from Cancun. Unfortunately, that departure time from Cancun means we'll probably have to catch the first ferry off the island, which I don't want to do because it costs us a day on the island. They did cheerfully switch us to a departure the following day but now we connect through JFK and get in at midnight.