Pensacola, Fl to Bangor, Maine

The DW and I are planning a trip from Pensacola to Maine to eat lobster and see the fall colors. We need help in planning a route using I 81 around the major cities. I' m needing help in trying to avoid the toll roads.......any suggestions will be appreciated. We are planning to make this a three month trip by following the colors south to NC.
We are driving a 34 foot motor home pulling a CRV.