Looking for service dept. in Dallas area

Does anyone know of a good mobile repair or service dept. in the Dallas or south of Dallas area? I just need one for general maintenance like winterizing my travel trailer. I have had two bad experiences at the dealership where I bought my new trailer and don't want to go back. Their sales and parts department are great but their service dept. is terrible. Please don't tell me that I could winterize it myself. I don't want to do it.