3 year old sailboat . . . should be in nice shape, so inspection won't be too bad.
Buying a sailboat is not much different than buying a powerboat. For a purchase of a boat in a different state, you need to research the boat registration requirements in that state so that you can be sure that the seller has the proper proof of ownership. You would want to see these documents (title, if required by the state, registration, etc). Then you want to check what the requirements are for your state as proof of prior ownership and sale. Usually states that require a title for change of ownership have provisions as acceptable proof when a boat/vehicle is purchased from another state not requiring the same.
NH -> MA is a good example. NH is not a title state for boats, but MA is. So MA accepts the prior NH registration as proof of prior ownership.
Also, since it is a fairly new, but fairly small boat, you would need to understand if there is a loan out on the boat as part of the original purchase.
You want to insure the boat from the moment you pay for it, regardless of its location at that time.
How to pay? I find that money (US Dollars) seems to be what most people want.

It is a matter of what buyer and seller agree on . . . cash, personal check, bank check, cashier's check, escrow, etc. Usually, the more money involved the more safeguards.
The seller will want to make sure the check or form of payment is valid before surrendering the title. If the boat has a lien from a financial institution , then the release of the title can take a bit longer.
Maybe tell us a bit more about what you are buying and when we can all go out for a sail
