When it comes to winterizing my coach - I don't do it. For the second year I have just plugged it into 50 amp service next to my house and turned the Aqua-Hot on and set it to 60 degrees. I also have sucked all the slides in and every 2 weeks me and the wife take it for a 50 mile run up the interstate. I also run the generator when making the 50 mile trip. I put 2 heat-pumps on line and cook everything for a good hour. So far I have had absolutely no issues with any of the bigger mechanical systems on my coach.
In contrast, last year my brother-in-law parked his in a storage shed in Junction City, OR, for 3 months and when he went to retrieve it - things were not good. He found out that his batteries were dead, had mice droppings inside the coach, had lots of moisture accumulated in de-humidified trays, had big flat spots on all his tires and some of his electronics had failed.
Just my 2-cents, so if you see me going up I-5 between Vancouver and Kalama, you all know what I'm doing. Not to mention they have great cheese burgers at the Kalama truck stop - that alone is worth the trip.