SOLVED. Adult fiction, published around 1919 in the US, actress lends car to Red Cross and gets involved as a driver. [s]

[Niels]

* found online, read 2018 - 2020
* in initial interview, main character offers "flower-vase" as important part of car
* main character's mother, a former circus (trapeze?) artiste, acts as her cook
* they may perhaps visit Atlantic City? (I can't remember)

[Lobstergirl, au gratin]

Is the actress serving in a war?

[Niels]

Coincidentally, a new search came up with the goods: Believe you me! by Nina Wilcox Putnam, 1919.
And I'm relieved to find that my memory is still functioning:
"Well, the first thing this bird asks me is do I know anything about a car? And I says, know what? And he says, well, can I name the parts of a car? And I says, yes; and he says for me to name them. So I says color, lining, flower holder, clock, speaking tube and chauffeur." [also trapeze artist and Atlantic City]

[Kris]

Glad you found your book, Niels. Here's the link - Believe You Me! by Nina Wilcox Putnam.