Below the bathroom sink is an access panel that exposes the power cord storage. The power cord goes to a junction box and I wired the unit before the junction box. There's plenty of space to mount the main unit on the wall in this space. I then ran the remote wire up through the linen cabinet next to the sink, went right along the sewer vent pipe so no drilling was needed. The remote is on the side of the linen cabinet next to the sink. I can see it from the kitchen if the bathroom door is open.
I wouldn't even consider a portable unit when the hard wired is so easy to install. If you sell the trailer, you can just as easily remove it.
I'll be at the trailer later this week and will take pictures, not sure if I'll be able to post but if you pm your email Address I can send them to you.
BTW, the unit did its job last week, my wife told me the microwave wasn't working so I checked everything and couldn't figure out what was wrong since the lights and fridge were working,finally dawned on me to check the remote and yep, low voltage was detected and the unit shut off power, after a few minutes the voltage came back up and power was restored. What threw me off was all the lights were working, didn't think of the battery taking over