What is the boat made of? Hypalon is easily stored deflated, dried, and rolled, but most other fabrics are better left partially inflated (don't keep them hard). We keep our boats in our "hillbilly hotel", one of those fabric garages from Costco. Anchor down each leg, guy out all 4 corners, and have it in a place somewhat protected from the wind and this will be it's 3rd winter. I prefer to keep it out of the snow and dry, but I like to keep them accessible for winter use so out of the snow is best for me. Our trailer sits in the driveway all winter waiting for that winter call.
Living in Montana, boating in Idaho