I did a 1/48th scale micro DC-3 out of depron and balsa some years ago. It is a 24" WS powered by an E-flite B-25 micro system. I don't know if this will be helpful, but here is the frame set up. It is a depron box with formers glued around it. I would think one could do this using the master series type of building. This is the plans that I reduced down to use as a guide.
Nice build, I am building a simular DC3 and can not figure out how the servo works with the front retract landing gear? Any help would be appreciated...Thanks