Speaking of winterizing in Tulsa. August 2014 my 3800 went to the dealer in Tulsa for the second slide repair. In November they called and wanted to know if I wanted to come up and winterize the RV or have them do it. I told them to go ahead and winterize it.
In December I retrieved the RV from the Tulsa dealer and brought it home. While preparing to set it up for occupancy I opened the fresh water tank to flush it out. To my surprise about ten gallons of water dropped out, pure potable water. I did further checking of the water distribution system and found what appeared to be a marginal attempt to winterize my hauler.
I called the dealer in Tulsa to complain that I had paid them to winterize the hauler but the fresh water tank contained gallons of fresh water following winterization.
Dealer dude said he'd call me back, which he did with the explanation that the shop dude did his part but it must have been the yard dude that didn't do his.
I dodged the bullet on that one but I'm sure it would have been my dime to handle any freeze damage that could have happened.
So,,,,,,,,,,I don't know which Tulsa dealer you use but I'd be damn sure to make sure your RV gets properly winterized.