Cab to Camper crawl-through
We were not originally going to have a crawl-through, but decided that it'd be nice in a pinch. I first designed something pretty large, but then decided against it, to prevent cutting and weakening the factory structure of the rear of the cab. The 435 has some integral roll and falling object protection, and I know that it works well as designed.
We simply used one of the rear window openings to make our tiny pass-through. We can wiggle through it if need be, but it's really great for inspecting the camper when driving down the road. And did I mention our dog Charlis thinks it's great too? He gets a queen-sized bed to sleep on, a front window and two side windows to look out of, and his favorite thing, proximity to Andie.
When the camper's frame was built atop the torque-free subframe, a rough opening was built to match the window opening in the cab. The finished opening flange (which bolts inside the rough opening) is constructed from 14 ga. steel and painted to match the rest of the camper...
This flange is made to accept a standard pass-through gasket available at most businesses that sell and install pick-up cap (toppers.)
From the outside, it looks like this...
On fairly smooth surfaces, this set-up works great, but with chassis flex comes enough movement to pull the gasket off of the flange. I've experimented with a little 3M WX-strip adhesive and it has kept the top portion together so far. Unfortunately, this is not a good plan to solve this problem since the gasket should be easily removable to facilitate raising the cab or shedding the box.
During the final "Phase III" of construction, I will experiment with other products and techniques to make this crawl-through better.