You know, that's very interesting and I believe you are likely correct, but (being honest here) I do remember noticing the word "ride" but it didn't translate for me into riding horseback. Maybe it was because when I'd gotten that far I was already plotting it out as a story taking place in the current time frame?

I just can't remember why the word didn't jump out at me, as it should have.

I think it could refer to a ride in a car, since he probably would be driven by a chauffeur and therefore be "riding," but I think it's more likely that your interpretation is correct. :)