I expect it gets pretty snowy where you are. I made the mistake of not covering last year, and every time I went down to do any work or check on the boat, there were several inches of snow in the footwell and on the deck making it challenging to move in the cockpit and open the companionway (some digging was required). When I finally did dig the hatch out and got it open, all the snow that wasn't brushed away, and a lot that was, spilled into the cabin.
Year before I kept a tarp over the boom tied down to secure points on deck. No frame, but the tarp didn't go over the lifelines. Planning on doing the same this weekend. It's quick enough to remove if you want to go sailing.
I like Caleb's idea of making another tent over the spinnaker pole. I'll probably do that as well, and point the bow into the prevailing winter winds to keep as much rain and snow as possible off the deck.
1972 Catalina 27