Be aware, there is no parking at the hotel, and your GPS most likely won't work due to the tunnels. The parking garage is here: De La Constancia 11, Zona Centro, 36000 Guanajuato, Gto., Mexico. It is very close to the hotel, but it is not so easy to get to if you don't know the area. It is just down the street. I packed a day bag to bring out with me and left my full suitcase in the car.
The hotel staff is great, and the services was excellent. I wish I would have known about the parking in advance.