At last, I have something to contribute to this wonderful site!
The cabinet doors in my 1979 13' Scamp
were too splayed to keep. So, I went to Lowe's bought a 4'x 8' sheet of 1/2" TC Birch/Blondewood plywood. I had a diagram on graft paper showing all the cuts I needed along with dimensions. Lowe's cut them all for me for free!
The wood was less than $35! It has a primed side. It can be painted or stained and will make nice strong but light
Hope this helps someone else, like all the advice in this forum has helped me!