If Riding Shotgun is the one involving some kind of "time travel", it is PHENOMENAL.
I read it a long time ago- I loved it because I love historical fiction, and the horse part is just kind of a bonus.
There was one sentence/paragraph (er, idea?) about a drunk driver (maybe motorcyclist?). I think the character also had her makeup tattooed on her face. Anyway, she got in a wreck, but she was so drunk she didn't have the ability to have a natural reflex and tense up- because she stayed loose, she survived.
Anyway, I always think about that when I'm reading about drunk drivers surviving crashes. I know it's more complicated than that, but it still pops into my mind every time.
Another little known RMB, before she started churning out the mysteries, is a book called "High Hearts" about a girl who disguises herself as a boy to fight in the civil war. Lots of riding scenes and historically accurate detail.
"Against stupidity the gods themselves contend in vain" ~Friedrich Schiller
I liked the RMB hunt books OK, the Sneaky Pie not at all.
Dick Francis I loved, especially the Sid Haley ones. All the horse stuff was of course right on, and the story line always moved at a good clip,(as they always say in the reviews ) with the mystery being interesting and not too predictable.
Jilly Cooper's are always fun,but haven't read her latest yet.
The Fiona Walker books were just a bit too long and too silly even for me.
Thought Tami Hoag's Dark Horse was good.
Another writer not mentioned yet (I don't think) is Jenny Pitman. She is an ex-steeplechase rider, and her heroine is a racehorse trainer.
They have the same ring of truth as the Dick Francis, but I like her even better.
There is a bit more 'horse stuff' in them, and her love of the horses shines through.
Yet another British jockey turned mystery writer is John Francome, and his books are decent too.
I haven't read a 'horsey' book in ages, and this thread has made me want to go get one!