Got some more work done on the bed, finished clearing out the cabover floor with the help of the missus (She found ripping it out to be very cathartic ).
The new bed platform has been partially assembled in a dry fit, but won’t be able to be installed until I finish some other areas first so I can rebuild the front step and safely get in and out of the cabover area.
At current, my only method of ingress and egress is to wedge my foot by the water heater or the propane compartment and try to swing my 350lbs up onto a very small ledge and not miss and go through the cabover skin.
I am still debating if I want to simply cut two layers of my very expensive foam board to go under the mattress or use the faced roll of bat insulation I already have on hand to under the mattress and fill all of the air gaps present between the top of the bed floor and the skin of the camper.
The rigid foam board would only fill in the space between the framing, still leaving the large gap underneath, where as the fiberglass would fill the entire space.
Once the tank step is partially assembled, I can use it to get up and dry fit the new floor, which will over hang the edge inside the camper by about four inches, adding the missing length needed to make the cabover bed area large enough for a standard queen sized mattress.
Because the original floor frame design was poor and the over zealous use of spray foam by Gardner in ‘75 (They seem to have taken the approach of, “We’ve got a new toy! Let’s Foam all the things!”), I had decided to build a second frame that would be anchored on top of the original, giving us 2x3 framing under the mattress and a solid beam across the front of the cabover near the window to keep the bed frame stiff and properly load bearing.
You can see in the photo below the 2x3 that will over hang the exisiting front edge of the cabover floor so that I can suck it up tight against the new floor and anchor the two together from two different directions.
Once the all the frame members are dry assembled and the new platform is test fit, it will be glued together permanently. Then the 2x4 front sill and stringers to go from the front edge of this frame under the shelf by the front window will be attached and the whole unit will be glued and screwed permanently into place.