I agree with 'BurbMan'. With the different layers of insulation, vapour barriers will lead to trapped condensation and then moisture, temperature changes perfect for growing mold.
I'm not really a member of the weight police, but all of the added things, walls insulation and finishings, wood trim, solar, lithium battery etc. all on an E350 chassis, the original RV was probably close to it's GVWR. I read the Craigslist on it 1994 model asking $25000,
Interesting, some nice finishings, but not for me.
Ken
2006 Winnebago Outlook 29B E-450.
2012 Honda CR-V AWD
Blue Ox Aventa LX tow bar and Brake Buddy Vantage.