Risks of Buying a Boat That's Been Sitting

Lets try this again. What are you looking at? Condition, equipment and time out of service.
It's hard to read your mind or understand what you wanting in our responses.
There are more to issues than a bout sitting for a while. Quality of mfg is a start; tined wires or cheap chines copper, Black iron tanks?
Plastic or other material for any tankage?

So fill us in on WTF your talking or looking at.
It could be Time Out for all we can guess.

Why not buy a smaller boat in good condition and see if you liked the lifestyle first?

If I was moving into the housing market for the 1st time, a large tumble-down 100 year old wooden home wouldn't be my first option to see if I liked the area.

Excellent explanation to give perspective...

No you wouldn't. Not if you couldn't afford to repair the roof, to replace the furnace, to replace appliances, to pay the exorbitant utility bills due to it's poor insulation.

In the price range you're looking, the boat is going to have many issues, that you can't afford to fix. So, it's going to worsen in condition, not improve.

You can live in it over the winter in Boston, but your cost of keeping it warm is going to be far more than a small condo or apartment would be, probably three times as much. Plus on the boat you will have monthly slip fees which will be nearly equal to what an apartment would cost.

I'd suggest you keep the idea in mind but work toward it by renting an inexpensive apartment and saving more money.

The last person I knew with a similar quest in Boston, purchased a nice older boat and she fixed it up herself. She had many times what you're talking about in her boat and it was a Hatteras. She spent one winter on it in Boston. She then sold the boat and moved to San Diego. She loved the boat as she used it on the trip from Louisiana to Boston. All was great. She was very familiar with winters in Boston. She wasn't familiar with winters in Boston on a boat.

There are many boats around that are cheaper with mostly cosmetic issues, but be careful. Mine was one. It sat for 6 years in salt water with little maintenance for 20 years. It had the engines, the room and size I wanted. Diesels are not damaged as easily from sitting as gas engines. Maybe the oily fuel protects. Other than a couple days of checks, light fuel cleaning, everything started and ran fine. The boat is wood, but with a copper bottom, so no marine damage. Lot of work on decks, cabin paint, etc. But the price along with my abilities (shipwright, mechanic) made it a bargain.
I never stay at marinas catering to yachts. All you do is pay more for more trouble and too many rules. If you scout commercial and private docks you may find dockage for half or less than marinas. Or docks catering to commercial boats. Yes you need liability insurance. Full coverage if your going to finance. These guys insure classic boats including boats under renovation: https://www.hagerty.com/Insurance/Classic-Boat-Insurance I don't use them now because of where I range, but they are a good place to start and they insure US & Canada to 25 miles out.
In Boston, insulation will save you money. My boat is 83' Monk design and I have several ways to heat. A boiler for hydronic heat if fuel is cheap, a pellet stove (with a water coil that heats the boiler), a wood stove (also with a coil), a diesel stove (coil) and electric if I'm running a generator. I live and stay in mostly cold or comfortable climates so don't use much ac. I am retired and am not bound to any place, but stay at a private dock in the winter for about $400/month. Generally I live on $3000/month that covers all expenses including fuel and maintenance. I haven't been married for years so don't have to spend on unnecessary bs. When I bought the boat, much of that went into rebuild and repair. Now I cruise a couple thousand nm a year. I mostly anchor or stay at fishing ports. I carry a small i/o for supply runs.
It can be done cheaply if you have skills and learn where to buy. Leaving behind the unnecessary frills of marinas saves a lot.

. . . it'd be better than a condo in a crammed apartment building.
Man o man, you don't know what crammed and jammed is until you live on a boat, rubrail-to-rubrail with other liveaboards in a marina. It can be a ghetto, with the drunk next door yelling at his wife, etc. Even cheap condo walls are better soundproofing than boats. And picking up and moving in winter isn't easy, with ice, winterized engines, etc. You did plug the exhaust lines too, didn't you? Otherwise, open exhaust valves will let some cylinders get rusty bores. And frozen toilets - do you know what a poop grenade is?

My friend you have no idea what your going into. Buy a big old boat that has been sitting you better have wheel barrels full of cash. Buy a condo

Did he/she ever buy that boat back in 2016?? I'd like to read that outcome.

We likely scared him right out of boating.

Did him a favor then.

Did us a favor then.

Maybe. After working in the marina industry, I figure the people who spend foolishly on boats probably support the industry for those of us who spend less foolishly.