As far as I recall, the dome seats could not be turned, with the exception of the swivel seats in the Santa Fe Super Chief 'Pleasure Dome'.I think domes are one of the most alluring features of rail travel. I also somewhat feel that the smaller domes with their face forward seating provided a more interesting view of upcoming scenery and also what your passing below. I really appreciated the fact that at night most lines turned off all but some floor lights so that a unrestricted view was possible also at night. Very cool gliding across the countryside at night with the hum of the car below.
As to the various trips, well I had to think about that a bit. Probably the first runs I made in a dome were on the Missouri Pacific St. Louis to Kansas City lines. Followed by the City of St. Louis which at the time combined with the City of Chicago that carried the famous Diner Dome. I never got to eat in it although I was in pullman, but it was something to see. Those City trains carried several domes on most runs. The Panama Limited and later the Amtrak City of New Orleans used the small domes at times. I also rode the Canadian National across Canada from Toronto to Vancouver which carried numerous large and small domes cars. The original Empire Builder had a number of domes as well. The Empire builder pre Amtrak surely was one of the great trains as for as imaginative interiors went. If I recall correctly the Blue Bird or the Wabash Cannon Ball also carried domes both of which I rode at some time. The Cardinal was a really interesting ride when it was in the small dome consist that preceded the super-liner equipment.
I also miss the ability to turn the seats to face various views that the new cars have eliminated for the most part.
The Superliners do have the ability to swivel certain seats in the SSL...
The Union Pacific domes had 'benches' for two instead of individual seats as in other domes, that were angled slightly toward each side.