If you want to avoid winter mountain driving, I would go the I75 route. It will be much easier travelling than thru PA and WV in the winter. The only mountains are going thru TN. There are a few steep grades around Pine Mountain area but it is generally easy driving, lots of places to stop for gas/food, no tolls until you get to the Florida Turnpike. If you take the I75 route try to avoid Cincinnati or Atlanta during morning or evening rush hour. If you can make it far enough, a good stop along the way is the Kentucky Horse Park. That time of year the park will be decked out with Christmas lights. There are also welcome centers at the beginning of every state on I75 along with rest stops and Flying J/Pilot type truck stops along the way as well. If you are thinking of taking I75 pickup the book Along I75, it has a lot of details about the route along with all the exits, stops etc.
Your GPS may also try to send you along the 402 to Sarnia to cross the border instead of Detroit if you go I75. I would not go that way, it will take you thru downtown Detroit (not on my to do). Go 401 all the way to Detroit, the mess in Windsor has improved greatly from the new bridge related construction.
