Many fond memories of summer trips to a KOA run by a friend of my father....at the KOA.
An excellent choice if one has an express option, but God help one's reflux if one is sleeping head-forward on a line that makes an ungodly number overnight stops at every single holllow log next to the tracks. I'm looking at you, [Southern] Crescent.Train travel...

Otherwise, yes, trains are great. Especially in Japan.