Well, this is a timely question, at least where I am concerned. Just had a dealer install a splendide 2200 combo unit in our 8291rk last week. They punched the hole through the woodwork and to the outside just forward of what looks like a plastic access cover low in the closet, below the plumbing connections. They mounted a black plastic vent housing to the outside. Looks great. They also recommended the drain pan for the machine to sit on, although they did not plumb the optional drain hose to the outside for it. They recommended the pan as additional insurance just in case. At least it would contain some of the water should a leak develop. Parts and labor came to about $2400. We have only ran the initial cleaning cycle called for in the instructions; this weekend we will actually run a load of laundry in it. We have the trailer at home, and set up in the back yard. We used the auto level system to level, but did not employ the front or rear additional stabilizers we use to eliminate the trailer "wiggles". Was surprised that we could not feel the (albeit empty) machine running, only that we could hear it. Not objectionably loud. With the TV on, may not hear it at all. It was only during the spin cycle that we could slightly feel it in the floor downstairs.
FWIW, at the same time, we upgraded the standard 6 gal water heater to a 12 gal unit, and added an adjacent spray port on the sidewall for the purpose of hosing off the Morryde fold out steps.
Dave and Darren
Max and Riley chihuahua/Jack russell K9 campers
22 Rockwood 8291RK fifth wheel
2019 Denali dually Duramax all stock.
BW companion, Blue ox track pro, timbrens, bilstein 5100s