By guided tour
For most visitors the simplest route is a day tour with round-trip transport from their hotel. You skip the driving, the guide handles the entrance and timing, and many tours fold in a cenote swim, lunch and a stop in Valladolid. Pickups from Cancun and the Riviera Maya usually start between 6 and 7 am to reach the ruins before the heat peaks.
By car
Renting a car gives you full freedom over timing. From Cancun take the 180D toll highway; it is fast, well kept and far less stressful than the free road, though tolls add up to roughly 500 to 600 pesos round trip. Leave by 7 am to beat the buses, and park in the official lot at the main entrance.
By bus
The ADO bus line runs comfortable coaches from Cancun and Merida, and Valladolid is the closest hub at about 45 minutes away. Buses are cheap and reliable but the schedule is tight: an early departure and the first return of the afternoon leave little buffer, so check times the night before and arrive at the station early.