I winterized my 2011 Greystone 29MK yesterday at the RV park we were staying at. It was my first time to winterize an RV. I was pretty well prepared by reading post on this and other forums and watching some YouTube videos. Thanks to RoadJunkie for the proper adapter to bring for the outside to black tank flush. My outside shower hose was barely long enough to reach the black tank flush. I bought a plastic 3/4" plug and barely inserted it into the anode rod location on the water heater. I used 3 gallons of antifreeze and would like to have had a fourth gallon to add more in the black and gray tanks which would have probably been overkill. I would recommend bringing a small brush to clean the threads in the water heater for the anode rod. After 6 months of use, the anode rode was in excellent shape but there was some white corrosion build up at the anode bolt thread. I used a 3" extension on my socket wrench and ended up with a good gash on the back of my hand, so use a 5" extension and wear leather gloves. It took a little muscle to loosen the rod.
When you remove the access panel to get to the water pump and back of water heater, mark the UP side on the panel to help finding the holes to screw the panel back on. I am 57 years old, 6'1" and 225 lbs and cannot reach the back of the water heater from the access panel near the UDC because of the small hole and tight quarters. I had to crawl into the storage from the curbside to gain access. My wife is 5'4" tall and too short to be able to lean into storage space and access it without a ladder. I will probably enlarge the access hole next year.