Larry, it's very basic carpentry that you can certainly do if you are reasonably mechanical, which you'd have to be to work with electricity and if you were able to take out the upper bunk without punching holes in the walls.
I saved the finished plywood on the bottom of the bunk and put part on top of the remaining part - aka shelf. Another part I used as a facia for the bunk raising effort. I used a piece of 1x8 pine for the aft side of the bed and 1x2 (mostly left over from the old bunk frame) to support the remainder of the edges of the bed. I added a small piece of the left over luan plywood from the upper side of the bunk to adjust for the wider bunk area, and built a support under it. Finally, I added some ribs under the side of the bed base that opens to the storage area as it was sagging a bit.
Virtually everything you need to do you can accomplish with a hand saw or a sabre saw, a drill motor to drive the screws, and a measuring tape. Level only matters if the trailer is exactly level as all points up and down are relative to the floor. Oh, yeah, and I bought some cheap U shaped plastic edging to go around the plywood for the facia to give it a finished look. I got it at Home Depo for about $2. The fact that I reused most of the wood, meant that the whole mod costs under $10 and it has worked out very well.
Also, if you'd like to discuss what I did on the phone after seeing pictures, I'd be delighted to explain in more detail.
F.