The real person to ask about this is Tim Martins.
But I digress. The civvie flight training I found most helpful in UPT was my instrument rating. Sure, there was a whole new set of AF procedures and manuals to memorize, but I had a good handle on the basics and knew what a VOR, ILS, etc, was while most of the bros in my class were trying to comprehend that while going through the UPT haze. I helped them out every opportunity I could, but I felt at least a little more relaxed.
So my advice from only my own experience, FWIW:
PPL in a Cessna or Piper
Instrument rating (or at least some flight time/ground school)
Good luck!