I still hold out hope that FlixBus* will improve cycletouring options in America. From their website:
https://www.flixbus.com/service/bike-travelCan I take my bike on the bus?
Yes, you can! Bikes are allowed on most FlixBuses, so you can experience great adventures wherever you want. Many buses in our fleet have a bike carrier at the back of the bus that allows you to transport your bike or are equipped with special bike covers, which ensure a safe transport in the baggage compartment of the bus.
Now that's a plus, my guess is to keep bike from damaging or greasifying adjacent luggage, bonus points if those are padded. I wish the airlines would have such things, it would save a ton of cardboard and no worries about storing a dedicated non-cardboard container for the return trip.