I think I would take a damp meter with me if I was going to have a look at
it why would the roof need replacing ? damaged or damp !or both and why did they have to clean out the fuel lines /tank this van may not have moved for many years and needs a thorough check with somebody mechanically qualified.
As a first time buyer I would be wary of American electrics, which not every garage will want to work on, Fuel consumption which is fine on american prices but can be steep over here.
I think it is fair to say that European manufacturers build for European roads. American roads do not seem as narrow or challenging or wiggly.
Me? I would love an American motorhome but probably not in Europe.
If they went to the expense and trouble of having the whole roof replaced including the insulation why did they leave the ceiling as they already had the new boards..
It's failed its MOT nearly every year on rear brakes which says it's been bodged to get it through each year.... Obviously don't want to spend correcting it..... Or probably any other faults.