Welcome to the forum. Lots of info here.
About 30 years ago (!!) I built a 14' Spindrift dinghy
from a kit. In winter, I put the mast
on two X braces made of 2X4's placed at bow and stern that put the mast
about 3' above deck
and then threw a tarp over the whole thing. The mast made it into a nice tent like structure that with a bit of breeze shaking the tarp now and then would shed snow nicely. Make sure there's no standing water
in the bilges, freezing could cause damage depending on what's in the bilge