After removing the back and rails, I cut a piece of plywood to fit snuggly inside. Using construction adhesive and a lot of weights to glue it down, I let it sit overnight to make sure the glue it is good and dry.
Leaving the back off while refinishing and spraying is best because it makes it a little easier to get the inside sprayed out nicely as well as the inside back, the part you will see from the front, painted as well.
I pretty much have this project down to a science and actually enjoy converting these pieces into a functional, fun and beautiful TV console.
Running a bead of caulk along the front and sides then touching up with the color give the piece a nice, finished look.