Gary, you pretty much got it. You don’t need to disconnect tank or pump lines; use the in-line valves in the pump’s cabinet to shut off the pump-to-tank line and open the line to your antifreeze hose. Make sure you’ve dumped any water in the tank though, and opened the manifold drains to clear existing water; but then close them or antifreeze will go there and drain out when you start pumping it. I’ve never had an issue with not draining or removing the icemaker filter that’s in with the water pump, but it’s an option.
The critical job here is to get antifreeze in the AquaHot, displacing any water in its coils. So when you turn on the pump make sure you get “pink stuff” at each faucet, including inside and outside shower heads, via BOTH cold and HOT handles. Your coach is larger than mine, so you may need more than two jugs of RV antifreeze to fill your longer lines, both hot and cold. It’s good to have a helper to monitor the jugs or turn the faucets, so you don’t have to run back and forth checking the jugs. Sometimes getting the fluid started into the pump can be difficult if draining lines caused it to lose its prime, so a little water left at the pump inlet can help at the start.
Don’t forget a cup of antifreeze in the washer/dryer drum and run one rinse cycle to protect its pump. I also remove the hoses on the icemaker water solenoid behind the fridge, and cycle it once to get water out; had it crack once, I guess when power went out during an ice storm or something. Or blow air through it while cycling, or cycle til antifreeze goes thru but I’ve not done that… antifreeze in the first batch of ice next spring, nah. You can cycle the solenoid to open its valve so latent water gets out by turning the clock mechanism inside the freezer or by (safely) applying 110v at the solenoid connectors. Admittedly I haven’t done that for awhile because the rig has been parked so long, so check your manuals, old posts here or YouTube videos, etc., for how to do that. If your coach is plugged in, theoretically the heat tape should come on at 40F and protect the solenoid, so you wouldn’t have to drain it. But an extended power outage might kibosh that. Your call.
Joel