Max elevation: 2123 ft / 647 m Min elevation: 59 ft / 18 m Elevation change: 2064 ft / 629 m
Max grade: 3.6% Min grade: -1.6% Steepness score: 12 + 361 + 905 + 43 = 1321
Distance: 1331.15 mi / 2142.28 km Travel Time: 19 hours 43 mins
It looks like one possible route that might be flatter would be to go through Montgomery (Texas), but make sure you double check everything if you're planning a road trip.
Elevation data comes from different sources and may not reflect true
driving conditions, so talk to other RVers if you're concerned about
Generally, it's flatter if you pick a route that's farther West, but this adds extra distance to your trip.
You could try I-75 to I-71 to I-65 to I-10 to I-95. That adds a lot of time, but it's good if you are on a leisurely drive and you want to see the Gulf Coast.
Basically, Kentucky and especially Tennessee is where you might have steeper hills to climb. I-65 through Nashville is generally going to be flatter than I-75 through Knoxville.
Taking I-77 through Charlotte, NC is generally going to be steeper as you go through the hills of West Virginia.
Remember to take into account road conditions. Interstates are generally cleared first, so they may be easier to drive if there's any snow.
Last thing is make sure you check your timing through Atlanta because there can be a lot of traffic. Try to get through before 3pm to avoid being stuck in slow traffic.
These are some of the possible highways along this route. Use the GPS in your car to verify all driving directions. If you're looking for campgrounds along the way, search for RV parks between Michigan and Florida.