Not necessary to fill the gray/black tanks with RVAF. You just want to cover the bottom and the exit drain to the dump valves.
If you can empty all of your tanks, leaving the low point and main fresh water tank, and gray/black tank valves open. That leaves a path for water to freeze along if it decides to freeze. You can then use your water pump to blow out the lines. The ShurFlo pumps are made to run dry for a long time. Run yours for an hour or so, then shut it off. Close the gray/black dump valves. Then I would pour about a gallon in total, into all the galley/bathroom sinks, the shower drain, and let some sit on top of the toilet bowl flush valve. If you have a water filter somewhere, make sure you empty it, too. Is it really going to be that cold for days and days that close to Albuquerque? I'm not a climatologist.
