we have the same camper with the same issue in the same spot.
Like you I have done all the roof maintenance and am sue there is no leak.
I was thinking about running a Pergo type floor over the top the entire trailer from rear to the bedrrom door. hoping that this would spread the load out accross the firmer supported areas.
My only concern is the added weight, any thoughts?
I have been underneath withthe belly off and can tell you the bracing option from that way would be almost impossible, and I really dont want to cu the floor if I can avoid it.
2006 Jayfeather 29n
2006 Dodge 2500 SLT laramie
Life is short so don't let your temper be..