You'll see UPS drivers with a pillow against their left shoulder and the drivers door window......nice and comfy ! Or your suitcase between the seats and you lie down on your side all curled up !
depends on how short you are. i would put a milk crate on the floor, between the driver/passenger seat, then my briefcase on top of that. not perfect, but i'd get some zzzz's many times.
Guy i knew took a wood board that was a few inches shorter then the entire cab and cut it into 4 peices which he screwed hinges into. He would just unfold it throw a yoga mat ontop of it and instant camp bed. About as comfy as it sounds but better then other options.
Chem Leaman and Matlack had only one seat in the R model. A lot of guys built a box [cut out for shifter room] to fill the space and topped with a good 3 inch thick piece of foam. Inside they kept blanket and pillow and extra clothing. Winters, when Belle, WV froze, we would run form Linden, NJ to Janesville WI. and I remember one guy who would layover 'on the box' on the way and hit a hotel after delivering and do the 'box' for his last layover coming back. Their boss paid $18.00 a layover [1978] so the one hotel night, with a good meal was covered.