302V: Travels through alternate universes and baseball

Possibly a book, possibly a series – listened to as an audio book on a car trip in the early 2000’s. The book was from Cracker Barrel (which is apparently Ingram Entertainment titles, if that helps). The book followed three protagonists, a girl and two boys. They traveled to other worlds or alternate universes through tunnels. The other worlds usually had some sort of baseball theme. At least one had a society of gnomes who used it as their court procedures. The girl protagonist was a pitcher. The had a map that helped them find the way – depending on how it was folded, it could show a neighborhood, a city or even be a star map. The antagonists had eyes you could see through, all the way to what was on the other side of their heads – photographs of Manhattan Project scientists showed that many of them were bad guys due to this effect.

263E: Summer vacation with a young child’s family

I can’t recall the title of the book and that’s my problem. It was a children’s novel that was about a summer vacation with a young child’s family. The details I recall is that the story centered around this young boy who was trying to make it to a baseball game in time during this vacation where free bats (or hats?) were given out at this game. He also carried around baseball cards in his back pocket. I know there are stops at hotels and things along the way. It’s from around 1987 to 1992. The cover of the book featured a hand drawn family where a boy was standing out in front of his family wearing a ball cap and tossing a baseball into the air with one hand. His family and their station wagon was featured slightly behind him in the background. If I can just get a title to this book, it would mean a lot.