It sounds like you should pick up a roll of 2" wide blue painters tape, it will remove easy without leaving behind a lot of flue on your truck paint.
Then cover the gaps on the drivers door, and leaving it shut, go for a test drive on the freeway. If it goes away, I would suspect the drivers door seal. Try the same thing with the passenger door.
If it does not go away, then cover the windshield, and go up the drivers side, then across to the passenger side on top and bottom. Test drive again at 60or so. Go away? Now it seems like removing and resealing the windshield will work to solve that problem.
Good luck,
Fred.