Clay and Jan Simon have a suggestion if you are planning on visiting Durango this season. They had the good fortune to hire a guide to gave them a very informative walking tour of the downtown area plus offered to do the same for the surrounding area as a car tour.
His name is Ben Pineda (618-812-8107). He and his wife Kupertina (618-203-6212) conducted the walking tour for $150 pesos/hr. Kupertinan is an historian and Ben is the translator. They can also be contacted at Kupercorral@hotmail.com.
Clay and Jan stayed at an excellent boutique hotel called the Hostel de las Monja, which is right next to the cathedral in the center of town and they highly recommend it.