2014 Truck Camper Building From Scratch

Capt Eddie wrote:
The structure for the cabover is not going to hold up. The structure should be full length along the sidewall. The OBS floor will be a problem no matter how much paint you put on it. Moisture is going to slowly delaminate. A solid 2 x 4 running along the top of the wall would support the bed a lot better. Your sheathing is not going to ad strength to the hinged cabover area. To fix the problem I see I would add an aluminum plate. 1/4 x 6" Full length. With counter sunk screws. The top 2 x 2 is the weak link for the bed. I would have some friends come over and put weight on the floor of the camper while two people get on top of the bed and jump around. Trying to break the structure. Even that is going to slight compared to the twisting and rocking it is going to do. Do this before you sheath it.

I disagree that it will not hold. The top bars are 2x3's (not 2x2) and will pull the cabover back when support is needed. I agree with you that the design of this detail is important and things need to be done in order to ensure proper rigidity of a loaded bed.
I say all this, not because I have extreme confidence, but that an almost identical structure has been tested for rigidity. I had your same doubt before I saw 2 people on the bed, with very little movement.
Of course these people were about 135 and 180 pounds, so I can't vouch for anything over 335 lbs. in the bed.:W