I would rent one for a long term test drive.
Due to the overhang and the mirrors and added difficulty of getting from front to back, I wouldn't take a cabover type c for free if I had to keep and use it.
It took us about three minutes to figure out the compromises made by building a house onto a cutaway. We Hated it.
Mine is an abstract, cartoonish (but true) example. It's meant to counter the standard view of 'money' being the main issue. COMFORT is the main issue and you'll have 1,000's of hours behind the wheel if your plan is successful.
What a shame to buy one and find out 1,000 miles down the road that the clostrophobic cab is not for you.
Your three questions:
Quality, is standard Thor
Value, is exactly usability and subjective as it equates only to you.
Reliability, is industry standard and doesn't vary much per model. Same fridge, same chassis, same heater etc.
I know nothing about Massachusetts taxes. I do know of the $3,000 add on if you don't finance through the dealer, the 11% per ent added tax, the licensing,the included top line extended warranty and goodies that made us choose a used unit with not tax....
Your low 90's offer seems $10k too high, or I've misread something.
Either way, a week of rental is a good idea that can't be combatted by rational people.