For a starter trip, come down through the townships to either the east or west side of Vermont, then drive VT Route 105 in either direction. There's enough to keep you busy for a full day, especially at the speed of 4x5 and by making a loop out of the trip you'll have easy highway connections back to Montreal. Next, come down via Sherbrooke as if you want to connect with I-91, but get off on Rt. 5 and start exploring the Northeast Kingdom Area of Vermont.