Thanks for the suggestions. I thought I would follow-up to report on what I found.
From the bottom of the vehicle, I drilled an exploratory/pilot hole at one of the corners of my proposed trap door, using a small drill bit that was about 3" long. To my surprize, after drilling through the thin waterproof outer layer, my drill bit went through about 2" of rigid foam insulation and barely made it into the coach floor.
The presence of a floor insulation layer was unexpected, but makes sense in our climate (Colorado), and the fact that the coach has tank heaters and such for winter camping. But the thick insulation layer also complicates the design of what I thought was going to be a simple 3/4" trap door, and the support flange I was contemplating to provide structural support for the floor rectangle I was proposing to remove.
So now I am wondering if there is any 2x2 wood framing I might run into in the insulating layer. Anybody familiar with the floor construction of the R-Vision Trail Lite 235s?
Thanks.
