Welcome to BP and come on over to the Short Term Rental part of the forums.  

Genuinely trying to learn here.

Even if someone gives you the lay of the land, you would still want to go there to see for yourself, just as you would definitely have someone come check out Dorchester to see what they consider safe and not safe.

I really don’t want to squash his enthusiasm, but I also don’t want him to get frustrated if he feels stuck. 

Yes to all of it.Definitely stay there a few days to find things your cleaners aren't going to notice.You need to create the 5 star experience from the beginning.

I'm trying to see how viable it is for him to buy a property there. 

Its easy to say that an older property cashflows better when you look at a spreadsheet.

I have to remind myself to have joy and be thankful.

Pay to separately meter the utility.

Rochester and Dover are seeing steady appreciation and rental demand thanks to ongoing development and proximity to Portsmouth - hard to find great deals here.