OK.... lets get an update here
I picked up some windows from a broken down camper. I got two of the larger ones and the one small one for $40.
I then cut out some frames using two layers or 1/2" plywood to match the walls. Once there are two layers of sheeting on there and the PMF and Butyl tape on the outside the inside edge of the window should be pretty close to flush with the inside wall. This will make it easy to make some nice wood trim.
I had a couple friends come over to get the frame onto the floor. The frame broke in a couple more spots during that process, but I got Humpty put back together and glued and brad nailed to the floor.
While sitting in the corner for way too long the frame was pretty out of square. To fix this I tied string to the bottom of the one wall and pulled the top of the other wall over until it was level. I am going to wrap the corners first which should keep it square.... I hope.
The slide out was pretty unstable as well so I went ahead and put on the first piece if Luan. I Kerfed it so it would bend, which worked pretty good, and wrapped it up over the top. I painted glue on all of the studs and shot in a brad every few inches. It really strengthened the structure.
The Kerfed radius from the inside.
The next video should be up in the next day or so. I have lots of editing to do.