This has turned into an interesting wander down memory lane.. I don’t have any records or mementoes of this trip, for obvious reasons.
From my best recollection, we had double bedrooms with en-suite for the NY-Chicago and Denver-SF legs, and slept in Coach from Chicago to Denver. This was probably because we booked as we went (no on-Line booking in 1978!) and being British, would have asked for “bedrooms” because that’s the British word, no roomettes etc over here.