Amtrak?
Many years ago, I organized a pecial group tour for 120 people from coast to coast. New York - Toronto - Chicago in two special coach cars and a separate dining car, then onward to Denver - Salt Lake City -Reno, we had 3 special Super-Liners, a separate dining car, and a separate panorama car (they even had to add an additional locomotive for the section through the Rockies). The last part from Reno to San Francisco again two extra coach cars and a dining car.
Amtrak provided us with all the best service, special menu choices (prearranged by us), and a lot of extras (a bottle of Californian wine when we entered California etc). The rest of that special program was arranged by us: Light show on Times Square, a visit to the Railroad Museum in Golden (near Denver), a huge barbecue at the Roaring Camp near San Francisco, luxurious hotels throughout, special dinners, and so on. A lot of work, but a huge success (we made about 400.000 $ with this tour alone). And as I'm a train enthusiast as well, I'd certainly this way way of travelling. As a passenger said: The train allows our soul to travel with us, whereas planes always fly ahead of our soul... 😎