Most solitude likely, beautiful trail but least views (only one viewpoint looking west at the top of the trail, but it's a fine one): Canty Trail up Blue Ridge Mountain.
Another beautiful trail, likely to be quiet and with some (but not wide open) summit views, is over Shrewsbury Peak from the CCC Road.
Deer Leap, up to the cliffs at the top of the Rte 4 gap, is short but has the views.
If you don't mind bumping into a few people at Killington, and can get a ride, it's 12 miles from the CCC road over Shrewsbury Peak to Route 4 via Killington & Pico. Just a few miles longer to walk it all the way to Gifford Woods. You could grab Mendon along the way if you want the NE100 peak, I think I remember peak_bgr did it from Little Killington.