I'm just finishing the transam tomorrow in Yorktown. My advice...do it your own way..it will all be good...Kansas was the toughest state for me in 110-115f no shade and headwinds.
Bug spray is more important than best spray. Bike shops are spread far and wide on the route and some are useless...pueblo, brecken ridge, west Yellowstone, Missoula were ok.
Rockies are long steady climbs mostly, Ozarks are short sharp rollercoasters, apallations/blue ridge are steep ...
People all along the route are used to seeing cyclists and are very helpful and freindly.
Dogs off the leash were an issue in Kentucky, Missouri, Illinois, and Virginia.
Navigation is easy with aca maps and or GPS files.
Finding fresh food along the wayvwad a problem..gas station food sucks mostly.
Traffic mostly friendly...just one issue in Colorado...otherwise all drivers courtious and bike aware ...except for the semi.drivers.
Lots if other stuff if you want.justmessage me