McCrea's film director goes on the road dressed as a tramp to try to get experience of the real world. His staff decide to accompany him in this amazing 'land yacht', a luxury double decked motorcoach equipped with beds, a kitchen, etc etc.:
Discussion on the Internet Movie Car Database identifies this as a Yellow Coach Nite Coach built in about 1934.
Preston Sturges directed this classic, which also includes a chase scene!
.....and of course there's Veronica Lake: