Ghosts Don't Ride Wild Horses (The Adventures of the Bailey School Kids, #44)

There are some pretty weird grown-ups living in Bailey City. But could the mysterious man that the kids meet on a class trip really be the ghost of Coyote Pete, the toughest cowboy in the
Wild West

Mrs. Jeepers' class is taking a trip to a pretend pioneer settlement in the wild wild west. But this settlement looks more like a ghost town. When a pale old cowboy shows up, the kids think he may be the ghost of an old bandit out for revenge.