I just did this swap out today. We never could stand the frosted glass! It was fairly easy. However, it did take several hours to do it the way I wanted it done...
The dealer was able to order a piece of tempered glass that was exactly the right size. The inside trim for the door window removed easily. If you do this, be careful because once the trim is off, the glass can virtually fall out into your hand. Also, the exterior trim is not secured, and can fall right out onto the ground (possibly causing the glass to fall if you have not already removed it).
I thought the glass would be locked in somehow, or "glued in" with sealant. The existing sealing mechanism was a rubber strip that goes around a groove in the exterior window trim. The window glass removed easily from this trim. to do it the way I wanted it done.
First, within the window trim but outside the glass, there was a large cavity with no insulation. In this part of the country, it can get quite cold and also quite hot. So, I filled that void with a reasonable amount of fiberglass insulation which had to be cut and fit into the space and around the screw holes.
I covered the exterior seal strip with a thin layer of silicone caulk. (During this process, I secured the exterior plastic trim to the RV using four small pieces of duct tape.)
For the inside trim, there was a strip mounting groove, but nothing in it(!?). I filled this using Mortite rope caulk, because that fit perfectly and was much easier than filling with a caulk gun.
I then placed the glass onto the exterior trim panel, and while holding the glass to keep it from falling out inward, put on the interior trim panel. I screwed the trim panels back together, and cleaned up the caulk excesses that were on the exterior window.
The result is a window that we can see out of while sitting on the couch when the door is closed.
DW is making a 3-layer cover for the window (black exterior, Mylar center to reflect heat and cold, and red fabric inside). That will be secured to the door with Velcro strips for privacy and to keep out light at night and hot sun as needed. This cover will be rolled up and stowed when not in use.
Pictures follow (the blue towel was just to keep the sun out of my eyes!):
Land of 10,000 Lakes
2016 Forester MBS 2401R