BoilerEE wrote:
Just did some snooping around in the basement area with a flashlight, and it looks like the main structure is supported by the outer edges and there's one longitudinal structural piece that runs right about in the middle with holding tanks on either side. I think I'm going to try some 2x6's laid flat under each side and down the middle under that spar, plus ones at the front and rear width-wise. The floor of the basement is 1" or 1 1/4" ply, so I'm not terribly concerned about support under the whole thing. Only going to use 2x6's because of the longitudinal "ribbing" on my truck bed - I think a 2x4 would be prone to get in between them and not spread the load well.
You are correct in needing to "spread the load" across your truck bed. You don't want all the weight on one side ending up on one sheet metal rib. There are pictures on this forum of some truck beds cracking because of too much weight being placed in one area. If you look under your truck bed you will notice reinforcing ribs which are usually where the bolts are that hold the bed to the frame. It is a good idea to have these point being load bearing. It is also a good idea to have camper guides that keep the camper centered once it is in place and a stop to keep the camper from bending the front of the bed.
Example:
