I built my TD in 2006 using an HF 1800# (rated at that time, now 1720 or 1740 # I think) trailer. My TD cabin is 5' X 114", or close enough to 5x10 that the difference doesn't really matter. I built the floor from ripped spruce 2x4s (nominally 2" x 1 5/8") with 1/2 CDX plywood for the deck, & 1X6" spruce for side rails. Sides were 'stick' built from inside out using 1/4" oak plywood for inner wall, 3/4" framing fastened with glue (TiteBond II) & a few pocket screws in selected locations, 3/4 blue (or pink) board high density foam insulation, outside wall 1/8" luan plywood covered with 0.040" mill finish aluminum. The spars were ripped from spruce 2X4s (1 5/8" X 1 5/8"), with a rabbet at each end to fit in a 'notch' in each wall. 1/8" luan sealed the inside roof with 1 1/2" high density foam insulation, again followed by 1/8" luan & 0.040" mill finish aluminum. The walls were fastened to the 1x6" side rails using 3" or 4" 'deck' screws vertically thru the 3/4" thick wall framing, before adding the insulation & outer skin(s). The cabin & floor thus built extends approx 6" either side of the HF chassis, approx 4" at rear, & approx 6" at the front before curving outward (& upward) another 6-8". My entire TD (including a group 27 battery, queen size 4" memory foam mattress, galley accoutrements, tongue extension, & tongue box plus contents) weighs 1180# including 200# tongue weight, & after 9yrs & 25K+ miles there is absolutely no distortion or sag of any component including that part of the cabin that 'overhangs' the trailer chassis.