In the latest version I have added a gcode window to the preview screen, so now you can see both the code and the path. When I want to watch it run through the code, like when Im testing the order of cuts, I just scroll down the code window, that highlights the tool path with the current line. It seems to me that does the equivalent of the preview.
The preview button on the main screen is a not a VB function its coded into Mach. I cannot get that from a wizard.