If I have discouraged you from riding across the U. S., I can assure you that it is doable and can be great fun. Maybe you have better climbing legs and a higher tolerance for dog attacks. Take the Trans Am. However, there is a new alternative to the eastern half of the TransAm. The Eastern Express goes from DC to Colorado in a more or less straight line. It was designed specifically to avoid the dogs and mountains of Appalachia and the Ozarks. 

(There is also a shorter connection to the Pacific Coast out west called the Western Express. It connects Pueblo, Colorado to San Francisco. Having ridden this route, I can attest that it is brutal. There are four 8,000+ foot mountain passes - Hardscrabble Mountain and Monarch Pass in Colorado, Cedar Breaks in Utah, and Carson Pass in California - to deal with plus innumerable climbs mostly in the basin and range area of Nevada. There are very long stretches with no services so you have to carry food and water. I was lucky that I didn't have to deal with extreme heat in Utah and Nevada. Your mileage may vary.)

Or design your own route as I did in 2018. My route stitched together parts of five ACA routes and worked great. I rode parts of the New York to Chicago, Northern Tier, Great Rivers South, Lewis and Clark, and Pacific Coast routes. It had plenty of variety and natural beauty out the wazoo. 

As for me, I happily would ride the Natchez Trace this fall but I have some scheduling conflicts. It will have to wait until 2025. 

So good luck, y'all.