>I am working on modernizing a rather large program that has hundreds of public variables, and user functions. It is wayyy low budget, so I am trying to recycle as much of what there is form, and object wise. All the public vars and user functions etc are in the program main.prg. I am using the form designer to build new forms etc, and in Dev mode, I need access to the vars/functions in the prg file - how do I achieve this?
>

break out the part where all public vars are declared/initialized into a prg like initPublics, call that from main.prg and in your Dev mode.
Warning: depends (as you posted) on the vars really being declared "public", not global privates first declared in main at program() level 1.
Having a special Prg for Publics might help later, if the job grows in budget and time: if confronted with maintaining such really last millenium practices, I opt to create a handful of public objects and switch most such vars into the object properties. If it is really hundreds, I massaged prg/vcx/scx also by program with a list of changes to be executed if at least some sane naming convention was used ;-))