Adding a washer/dryer to your RV
My new SALEM came with the W/D hookup, but no vent. They probably do it this way because different model washer/dryers have differing vent locations and you usually don't really have enough room between the unit and the wall for routing an exhaust pipe. The vent has to run straight out through the exterior wall, and the hole has to be exactly in the correct position. The do-it-yourself owner has the option of buying a stackable W/D pair and a matching metal frame to hold the units (or add a shelf to hold the dryer as I did), or buy one of the W/D combo units. I previously had some bad experiences with the combo unit in townhouse we had - it was low capacity, a bear to move, difficult to work on, expensive to repair and cost a lot more to begin with. So I put medium sized matching W/D units in our RV (on sale at Sears at the time) after adding a reinforced shelf in the space for the dryer. I ran 2x2's from under the shelf down to the floor because the closet walls are too flimsy just to screw in a shelf and if you don't, you might find your dryer smashed down atop your washer after a hard ride. Doing it this way means that you have to build the shelf (or erect the metal support frame) and place the dryer exactly in position so you can determine the precise placing of the dryer vent tube to make sure the dryer outlet, vent tube and exhaust vent housing line up perfectly - only then should you cut the hole in the side of your RV. This is really a case of measuring twice (or thrice, or...whatever) and cut once, since it is somewhat difficult to move a 4" hole once it has been cut out of the side of your RV.
Another reason I bought matching units is they are much easier to handle within an RV when you are installing and repairing them. I even took up Sears on their offer to deliver and install the units into the space I had already modified since it included hoses and a full guarantee that everything was hooked up correctly. Fortunately I was able to get the vent hole exactly positioned by measuring and remeasuring several times, but unfortunately the installation resulted in a wet floor because they neglected to open the outside drain valve into the gray water system before doing a run test. And be sure to open a nearby window on the opposite side when using the dryer, otherwise you will end up with a lot of humid air being leaked back into your RV and adding a lot of extra running time on your dryer. All in all, it took a lot more effort than I anticipated, but once done, it was well worth it - especially since my wife loves it.