I just re-climbed Frissell on the 27 of December. There is some kind of construction just north of the Jeep Trail's intersection with Mount Washington Road, apparently some new road is being built. There was a log placed across the road. You can still reach the regular trailhead by hiking north on the road for 1.2 miles to the border. As of right now, there is little snow on the summits, so they are still pretty easy to climb.
NOTE: If you have climbed Mount Frissel on or after the 27th of December in 2001, PLEASE post it here. Thanks!