Jim, it sounds to me like what you're planning is to take a 44 year old MH down to the chassis, increase the width by almost 50%, increase the length by 25%, then build a new box up on top of it.
While I applaud your gumption and initiative, think about this. It's an E-100 chassis. (I used to own an E-100 van.) It's probably overweight as it sits right now. By the time you're done you'll be several thousand $$$ poorer and probably have a MH that is essentially undrivable. I would suggest an alternate plan.
John & Diane, Fulltimers. RVM103 NHSO
On the road since June '12 with Lincoln, the guard cat.
2002 Dutch Star 40, Freightliner, Cat 3126, 2004 Element