My wife and I took our new RS26 out for a short shakedown drive and she immediately started complaining about being "roasted" by a blast of hot air coming into the cabin from between the cabin floor and the RV floor. The picture is taken from behind the drivers seat showing the 1" gap that runs the entire width of the cabin. When we picked up the RV there was a piece of carpeting tacked in place but did nothing to close off the gap.
I took a piece of 1" round close cell foam, 6' in length, and crammed it into the gap. This completely sealed the cab from the outside, and then covered it with a piece of 2.5" wide PVC wood-grained door trim. It more or less snapped into place and is held in place with 5 screws.
The floor between the drivers and passenger's seat also gets hot from the transmission. So I applied a piece of Thermo-tec adhesive heat shield material to the underside of the cabin floor directly above the transmission. It didn't eliminate the problem but mitigated it significantly.
Another issue I had was with the wiring to the sensors on the black and gray tanks. Here is what I found when I first looked at it.
After several hours of work properly wrapping and protecting the wiring and then covering the sensors on the tanks with Gorilla tape and Flex Seal, this is what both tanks look like.