7 Month Retirement Road Trip

We are just starting to plan our 7 month road trip from the UK, covering as much of USA & western Canada as possible from April – Nov 2020, ending in Churchill to see the polar bears. Our aim is to cover the lower 48 & Alaska, Hawaii will have to wait. Flying in and out of JFK, hiring a long term rental SUV.
We have seen quite a lot of the USA on previous trips, Rocky Mountain NP, Yellowstone, Yosemite, Grand Canyon, Arches, Canyonlands, Grand Teton, Glacier, Sequoia & Kings Canyon, Monument Valley, Blue Ridge Parkway, Big Bend, Mt Rushmore, Devil’s Tower, Route 66, west coast north to south and so on.
We plan to re-visit some as well as the major cities we haven’t yet seen such as Washington DC. We enjoy seeing the tourist areas, but prefer to see the back roads and small town America. We enjoy doing railroad trips, loved the Durango to Silverton railroad. Would appreciate any advice, hints, tips as to routes, must sees, no matter how small, or off the beaten track. Thank you.

The Great American RoadTrip Forum – Planning Summer RoadTrips