Our Montana is the 375FL High Country model. It has a rear door on the opposite side. Originally, it came with only 1 awning (on the normal front side). Because we planned on using the rear door (actually more than the front door), we wanted an awning on that side also.
When we purchased the camper, we worked out all the logistics and the price when we took delivery and then had to come back about 2 months later and they installed a new awning on the opposite side. It worked out great and we've been very, very happy with it.
It is electric, they were able to install LED lights (same as the front side), and even installed the power awning to attach accessories (like the flood light or the fan).
Yes, they ran new electric wiring from the converter to the end of the trailer. The wires follow the frame of the trailer and they installed 3 new switches. Our bedroom is in the rear (front living room) and the switches are actually on the side of the dresser drawer cabinet. The wires come through the floor from underneath. There are 3 switches: One for the awning, one for the LED lights, and one for the power awning strip for attachments.
The wires are fed back under the trailer, along the frame (inside the J-panel) and then into the back closet through the floor. The back has an outside cubby on the bottom of the closet. The closet floor is the ceiling of the cubby. The wire then runs inside the closet, up the wall in the corner and out to the arm where all the power goes to for everything .... including the new LED lights.
So, yes, it can be done. The most important thing you need to do is measure exactly where your wall studs are located so you can anchor the arms of the new awning to them. The measure again to make sure you can find an awning that will actually be the right length to fit and the arms will actually hit both ends where the studs are. Otherwise, you'll need to drill holes completely through the wall and put an anchor inside the camper. Then figure out a nice way to camouflage the hardware inside the camper.
We also had a new stair way arm - handle installed on the back door, like on the front. They installed the screws into the wall and did not hit studs. After a few weeks, the screws started working loos. They finally would not tighten at all as the fiberglass side simply stripped out. I ended up drilling holes completely through the wall, ran some long thin bolts completely through the wall and put washer and nuts on the inside of the camper. Yes, it looks a little funny inside the camper by the back door if you really notice it. But functionally, the outside stairs grab bar is rock solid and it's never wiggled since.
So, that's why is so important to make sure you hit studs, or plan on anchoring by going completely through wall and anchoring from the inside.
