The Silver Penny — Randall Wright

Deb figured if he had to clean out Hilde's stall one more time, he'd bust. He wished he knew the hex for making all that manure disappear.
Grandpa said the German folk down in Pennsylvania knew how to do it. But Grandpa could barely recollect the cure for the wanderlust, let alone the more useful hexes.
"Well, maybe I'll just work it out on my own," Deb told himself.

A young boy goes on the journey of a lifetime . . . or many lifetimes

Deb has a bad case of wanderlust. No hex can keep him from yearning for far-off places, and neither can a broken leg. But it can keep him from moving around at all. Deb is so miserable that he even misses doing chores. Nothing cheers him up-not his cousin Tam and especially not that strange boy Bray who's been hanging about.

The only glimmer of brightness in Deb's life comes from Grandpa's lucky silver penny, which keeps mysteriously showing up. Soon its strange powers lead him on a journey that might be just the cure he needs.