So far I bought plane tickets. I did not make any other reservations yet. The summary of my current thought on my itinerary is: Arrive in Merida on December 24th, train to Campeche right after leaving the airport, 4 nights in Campeche, 3 nights in Mérida, 2 nights in Valladolid, one night in Cancún. I could be persuaded to change this and/or take the bus instead of the train.
On December 24th, my plane arrives in Mérida 2:51pm. On January 3rd, my plane leaves Cancún at 8:45am. On December 24th, the last Tren Maya of the day leaves at 7:29pm. There are 4 hours, 37 minutes between the time the plane lands if it is on time, and the time the train leaves. Various sources say to arrive at the train station 30 to 45 minutes in advance, and that it could take about an hour to get past passport control and pick up my luggage. Then who knows how long it will take for an Uber or DiDi driver to show up. Google maps says it could take up to 37 minutes (if traffic is good, and google always underestimates driving times). I am not going to rent a car.
Is there any chance I would be able to buy some bottled water and a little bit of groceries, sometime between leaving the airport and arriving at the train station and still make it onto the train?
Or should I just acqauiesce to making Mérida my first city?