I'd pick all the colored ones. They'll finish ripening indoors. You can cover the plant with a frost blanket. Make sure you bring it all the way down to the ground to trap the heat in.

Picked about 40 lbs of green toms this morning. The temperatures are 5 degrees below prediction, so I expect a freeze at the airport and a frost here in suburban areas. This is SE MI.

Posted on your post of this question on the Tomatoes forum. Pick all the ones with color. You gain nothing by leaving them on the vine anyway once they reach color break (blush). Cover the rest - no plastic.

dave

I've had tomatoes survive 32F+ without cover, but that's with no frost. If you don't have frost cloth, anything non-plastic will help. A couple of degrees protection can make a big difference. I think plastic will also help as long as it doesn't touch the plant, but I'm not positive about that.