We installed a washer/dryer in our trailer!
As of writing this it has been in constant use for three months and we LOVE it!
We were lucky enough that we had a closet in our fifth wheel that was the perfect size to add the unit. A lot of RVs and trailers actually come pre-prepped to add a washer and dryer! If you are interested, check to see if yours is already setup for it!
Ours was not, but because of where the closet was, installation was actually pretty easy! We did have to run electrical and water into the closet but if you are mildly handy, this can be easily accomplished.
The scariest part was drilling a 4″ hole right through the side of the trailer! This is for the dryer vent and it went fine, but its still a scary notion!
The unit we bought was the Splendide WD2100XC combo unit. We did hours and hours of research from blogs, you tube videos, amazon, etc and settled on this unit and so far we are very pleased! It is RV sized so you can only do small loads but the unit washes and then switches to dry so when its done, you are already ready to start the next load!
Feel free to ask questions if you need install help!