I had the few drops of rain leaking onto the dash a few years ago. In my case, it was not coming from the windshield. It was coming from the clearance lights above the windshield. I finally solved it by caulking the lights with clear silicone. That solved that. I realized that it would be a pain when I had to replace a clearance light bulb, but that hasn't happened yet.
The windshield shifting. I also had that. There are different approaches to this. I chose to try a cost effective (cheap) approach that I could try myself. I used 'The Right Stuff' by Permatex or Loctite. It is black. It is marketed as a gasket replacement for engines. It is not silicone. It sticks, it really sticks! I caulked the windshield to the rubber gasket. That solved that. Our windshield has not shifted in the rubber gasket for the last three or four years.
2016 Creekside 23RKS
2012 Ram 2500 Laramie 4X4 Cummins 6.7L