If you’re serious about scrapping the VW appoach, you may want to look at my build thread. I threw out the frame that came with my kit and scratch built a frame based on Mustang II components. I have also considered other approaches, such as MGB, Chevy V6, Buick aluminum V8. If you don’t go the VW route, the driver is the width of the rear end. After that, the rest falls in place.
See Building Alfred under My Projects.
Looking forward to your progress.