Here's what I've done with my 128, hope it helps--I'm no expert at this.
Drained water heater, put the anode back in to keep rust out, turned the water heater bypass valves all to bypass position.
Took out the large water filter, took it in the house to dry out. Then it can stay in the camper (but not installed) for the winter. The small screen filter in the water pump intake line can stay--it emptied when the lines drained.
Drained fresh water tank, opened faucets (including the outside shower faucets), opened the low point drains in the water lines. Left them open a day or two.
Installed a bypass valve in the input line to the water pump so I could fill the lines with antifreeze without also having to fill the freshwater tank. Thus, used just over a gallon of antifreeze instead of the estimated 7 to 10 gallons needed otherwise. Then used the water pump to pump the lines full of antifreeze, including the lines to the outside faucets, and put about a cup of antifreeze down the sink drain.
Left faucets and drain closed. Shut off water pump (I almost forgot this ).
Took all the cushions in the house for the winter.( Not sure this is necessary but used to do it with our sailboat.)
Inspected caulk joints and repaired a couple.
When I put it away I'll prop the compartment lids open slightly and open the cupboard doors to allow air circulation, then set up the desiccant, Damp-Rid, which I got at Ace Hardware for about $11, including both the absorbing crystals and the plastic holder/water collector. Then I'll take the battery and its box home with me where I can keep a battery minder on it. I should make sure the tires are up to the full 60 pounds.
What the manual says I should do but probably won't is to set the camper up on blocks or jack stands.
That kept me busy for some time, hope the list helps. I'd have forgotten the shower faucets if I hadn't seen a mention here.
It's never too late to have a happy childhood!
Lee, WU0V, and Courtenay, N0ZDT
2011 Rockwood A128
2000 Silverado 1500 pickup
60W solar system
2000W inverter generator