>>1910852>wool blanket instead of an underquiltMaybe, with some work. An underquilt cinches up tight on its head and foot end, while the rest remains close to the user but not smooshed against him. The idea is to trap warmth (or not cinch it as tight, so you don’t get hot, like unzipping a sleeping bag). You can’t just tie up a blanket from it’s corners, you’d need to rig it with shock cord.
And it might work for shoulder seasons, but probably not for winter. It gets cold as balls in NJ or NY or Massachusetts or wherever.
Another option for shoulder seasons is a no-sew poncho liner user quilt (pluq). It’s not the lightest or warmest thing out there, but they’re fun to make, easy to find the pieces you need, and pretty cheap.
