In part 2 of a two-fer (I actually finished The Cat Sitter's Pajamas a few days ago, but it took me a few days to do the write up), we find the Hitchhiking ghost Rose Marshall explaining the role ghosts of the road play in their corner of the InCrypted universe. (Rose gets mentioned very briefly in Half-Off Ragnarok.)
Sparrow Hill Road by Seanan McGuire takes a rather roundabout route in narrating Rose's story. rose herself states in the introduction that the dead's sense of time is off kilter. The narration also is told in a series of vignettes, which doesn't lend itself well to linear narration. The end result starts off very messy, but winds up becoming more and more engaging the further in you get.
In a more linear fashion, rose starts off as poor white trash south of Detroit. A better off boy in her class asks her to prom. The night of Prom, he doesn't show up. Rose decided to go out to his house and confront him. Out on Sparrow Hill road, Rose gets run off the road and dies. Her ghost catches up with her date, who had a car issue and was running late. Given this was the early to mid 1950's, cell phone was not an option.
So, Rose has become a double threat. She's a type of ghost classified under supernatural taxonomy as a Hitcher. She also works as a psychopomp, escorting those that die on the road to their final destination. As a hitcher, she can take a corporeal form if she's offered a jacket (traditional) or some other form of clothing. she can also eat that which is freely given by the living. She has several epitaphs based on ways her story has morphed over the years. (In some, she protects travelers, in others, she kills them.)
Her cosmology can be simplified to Daylight being the normal physical world, the Twilight dwelling of ghosts, and Midnight houses "deeper powers". Other supernatural things exist in here, with the crossroads being where people and people who used to be people can go to barter.
Rose spends much of her off duty hanging out with a Bane Sidhe at the Last Chance Diner.
As the book progresses, we learn that Rose's ultimate goal is to get one Bobby Cross off the road. Bobby being an old film start who bargained at the crossroads for eternal youth. As the price, he now much feed the souls of innocents to his car. Bobby drove the car that drove rose off the road in the 50's.
We also get strange reunions with people she either saved or psychopomped for, old family and friends.... even random strangers.
It's a very interesting, if not quite cohesive, read. I'm kind of wondering if rose's story will continue or if she'll be relegated to occasional cameos, particularly since McGuire already has 2 series going on, and a third would probably kill quality. On the other hand, the expanded cosmology of the ghost roads is quite fascinating, and something I would love to see explored in more depth.