Welcome to the forums here at SBO.
It is difficult to understand how you feel about the vintage boat interior.
It was the late 60's and early 70's when plaid leisure suits were all the rage.
Sailors in Board Shorts and women in plaid.
It might have helped if you sucked a sugar cube or found a dot from back in the day.
I do understand a new boat and a desire to upgrade.
If the cushions are still good, then all it will take is some fabric that suits your style.
Certainly, a loft can be helpful with canvas, but
@kloudie1's suggestion of an auto upholstery shop may be less costly.