While winter may be the best time to visit the Grand Canyon, I don't think driving from Delaware in the winter is the best idea. Not uless you went south to Ga and then across. Taking the straight route across W Virginia, Pa, Ohio, etc, if you say weather is a big issue, I would wait at least until March to go and would still make sure you had a weather window without snow or ice. It is not just the best time to visit, but the best time to travel you need to be concerned about.
Dan and Kathryn DeBruin plus dogs
2005 Newmar Dutchstar 4009