With the glass windows out, we are replacing them with 24 guage sheet metal, a layer of 1/2" foam board and then 3/4" plywood cut to size. Another bonus to having some of the windows out is some much needed insulation! Maybe it will keep some cool air in in the summer and cold air out in the winter.
Jim Bob went to our local AC place and bought sheets of metal from those guys. He then took it up to the metal shop at school where he cut it to fit the windows using a foot shear and put this nifty 1" lip at the bottom to hold the metal in place, to give the metal rigidity and to give some surface area for the caulking. He made the bend by using a metal brake.
A sheet of 3/4" plywood was then cut and placed on the inside of the window to finish it out.
Jim Bob screwed it all together from the outside being careful not to screw all the way through the plywood on the inside, leaving a nice clean surface to work with later on when we want a backsplash.
Jim Bob has a nice little helper these days.
We are replacing six windows on each side of the bus. I think eventually we will put a little window in over the kitchen sink for a nice view. This picture shows four windows complete and two windows lacking the foam insulation and the 3/4" plywood.
It is nice and clean on the outside too.
Here is a video showing the installation of one of the windows. In Jim Bob style, it all fits together nicely.