Hi Courtney,
For more of my expounding on the seacoast NH, please check my prior posts on the subject (I'm on mobile so trying to keep this brief). Aaron above mentioned Farmington, Somersworth, and Rochester as good spots for investing. This can be true from a strict numbers standpoint, but as you want to be an owner-occupier, I'd suggest you look beyond just the numbers.
These are the worst towns in the seacoast from a reputation and crime standpoint (crime, relative to the nation as a whole, is low everywhere in NH however). There are great investments there to be sure (I am negotiating one right now in Rochester), but if you are going to house hack I would implore you to make sure you know the neighborhood you want to buy in in those towns very well. Generally no one who rents in these towns is living there if they could afford somewhere else in the seacoast, like Dover, Durham, Portsmouth, Newmarket etc.
If you end up buying a rental on Lafayette St in Rochester or Green St in Somersworth...I don't think you are going to enjoy your time there. I know I wouldn't want to live in C/D areas with C/D class tenants sharing walls with me. Here's an example of what I mean. Go to 5 Lafayette Street in Rochester on google maps, and look at the street view of that area. Then tell me if you want to live there. Out of town (or as is more usually the case, out of state MA investors) are making very good money in downtown Rochester. I know a few who do so personally. But I also have plenty of stories working for a property manager that worked on these types of areas in these towns. Missing doors, missing toilets, animal and human feces on walls and floors, piles of diapers, drugs, guns, police, police, police etc. You're gonna need a strong stomach. Or maybe you'll get lucky, who knows.
I am not attempting to dissuade you wholesale from these areas, but just to think critically about them. There's money to made in Berlin too, but I don't see that being thrown around as a great place to house hack. The numbers for an absentee investor and one who is going to live there are not apples to apples. It's easy to pass off low end tenant management to a property manager; it's another thing entirely when you share a house.
I'm on my phone so I've tried to keep this brief. Again I've said much more about this area in the past. Hit me up if you'd like to chat further.