I've taken the Amtrak Autotrain from DC to Florida many times with a car and family. It is somewhat expensive (about $2,200 roundtrip for a family of four and car) and very unpleasant but I keep WISHING this time will be different...the US sleeping cars are ancient and covered in a film of grime. The tracks in the Carolinas are very rough and bumpy, sleep is difficult. Maybe someday we'll have sleeping cars like this but I think we'll have luxury self-driving sleeping buses displace America's terrible sleeping car rail option.