weight certainly does add up... My U Haul is a simple weekned warrior hauler... back 16' is the garage for my 04' TJ (5000 LBS fueled up) and the front will be a futton small galley with the matress up over the cab. I do not think I am adding another 600 lbs in windows insulation paneling cabs and furnature... the FRP I cut out to insatll the windows weighed more than the windows themselves... and I ditched the bench for two air rides and cut a pass through from the cab to the box... the big savings is NO facilities (bathroom) Instant heat and 45 gallons(aprox 360 lbs) of fresh water will be the heaviest addition ... pottapotty in the garage for emergancies and an outside shower set up...
again only a weekend warrior sorry should mention 1989 S1654LP 26' box