Its a lovely little town between the sites of Coba and Chitzen Itza, on your way to Merida if you come from Tulum or Playa del Carmen.
If you wish to get some local dresses or shirts, this is the place where to get them 3 times less expensive than in the touristics cities.
You will for sure, like the few lovely restaurants with reasonable prices. See what I wrote about El Atrio.
The Main thing to visit in Valadolid is the Zocalo, the original line dates from 1552 but has been modified over time. And it is an excellent place to take a break between tours as not only their benches, trees and walkways are nice, you can admire from there the Municipal Palace, the Church of St. Servatius and distinctive source which is a monument to the mestizo Valladolid.
While driving, you will not miss the colorfull houses that are part of the charm of Valadolid in Yucatan.