Seeing Chichén Itzá Along the Way;
Without a Stopover in Pisté
If you have some lack of time, you might consider stopping at Valladolid for the night and seeing the ruins early the next day on your way to Mérida. There are regular buses to this pleasant city. There are also regular ones from there to the ruins and from them onward. An advantage of arriving in time for the 8 AM opening is getting to see the site before the tour buses converge.
To get started from the airport, you would get onto the bus into the Cancún bus station. Going onward to Valladolid will take another 2-3 hours, so gauge how late in the day it is and how energetic you feel. There are plenty of hotels near the Cancun station. Also, first class buses to Valladolid do not go at all hours. Check the ADO website to see when they end if you are arriving later in the day. However, there will be second class Oriente buses (ADO owned) departing later on into the night and the wee hours.
As I understand it, it will take around 45 minutes to get there, and there are vans (combi's) from Valladolid to Chichén Itza just across the street from the bus station. They usually leave when filled. You can take whichever option leaves first, and either will drop you off at the ruins.
When you are done seeing the ruins, you can go out to the bus
stop in front of the site and hop the next bus to Mérida. This will take around
Some Places to Stay in Valladolid
Albergue La Candelaria Youth Hostel advertises breakfast, a complete kitchen and bicycles for rent.
Hotel María de la Luz is nice for a splurge and has a pool and parking.
Hotel San Clemente is also a nice splurge with pool and parking. They also had some rooms that were a bit
cheaper than listed on the website when I stayed there. This place was a thorough pleasure after biking there from Mérida.