22' travel trailer rebuild from the frame up - NEED HELP!

I built a TC a few years ago. A fun project. I think I would save as much as possible from the old TT. I wouldn't keep the frame. I would buy a heavy duty flatbed goose neck frame. Building from that point you wouldn't have to worry about weight. I can say with that building experience, those engineers that design RVs do a lot of calculations to keep the weight down. I wanted quality and of coarse the weight went up with the quality. It turned out nice but extremely heavy.