As long as they don’t freeze SOLID, they should be fine. I’d harvest any where the stems are coming away from the vines, but I wouldn’t worry about the others while you’re gone.
If using straw would make you feel better, then do that if there’s a chance you’ll have a few freezing nights in a row while you’re out of town. Or a tarp or sheets would be fine, too. Winter squash are pretty tough! :)
Everything I have read says to NOT LET THEM GET HIT WITH A FROST!!!!!!!! under any circumstances.
Except for one site that said a light frost wouldn’t harm them.
Some of mine are almost ready, good tan color, hard rind I can barely dent with my fingernail. The stems are still green though and a couple sites said that when the stem dries out and turns brown is one of the good indicators that the squash is ready to harvest. Some of them have just a vein or two of green left coming from the stem but otherwise are nice and tan with a hard skin.
I thought by Sunday, before we leave, I may at least harvest the ones that are most ready and bring them in to cure while we’re gone. That way I save at least some of the crop in the event there is a frost. The forecast is for partly cloudy, to that makes a frost less likely. It’s those clear nights, like last night, that you have to watch for.
Aside from straw, I thought that maybe just laying some pieces of cardboard across the plants would work for frost prevention but still allow for good air circulation.