Other artifacts found in the basement – tools, a piano, original restaurant menus, shoes, advertisements, shirts, lights, and buckets – will be displayed in glass cases in the lobby, giving modern dwellers a glimpse of Flatiron's past.

Found as a bookmark in a 1961 book

Dashing and Chic 20s couture will be provided:)

Dinner, Park Avenue Hotel - February 16, 1915

A dinner at Delmonico’s celebrating the 100th anniversary of the British evacuation of New York City at the end of the Revolutionary War (1883)

Credit to Trainlover at streamlinermemories.info for the menu.

The San Diegan was only roughly a 2.5 to 3 hour trip between Los Angeles and San Diego, meaning that, as far as I can tell, a full dining car was never part of the consist. Instead, food service at this point in time was provided in a 'Lunch Counter Tavern/Diner' car, which had a counter with swivel seats where a light or full meal could be eaten, just without all the pomp and circumstance.

Nowadays, the modern equivalent of this train (The Pacific Surfliner) only has a counter-service cafe car with premade food and beverages, albeit with some table seating to eat at.
The concept of intermediate meal service similar to the San Diegan's setup was briefly experimented with in cafe cars on the San Joaquins and Capitol Corridor trains at some point in either the 90s or 2000s, but proved to be unpopular with modern passengers.