The Dastardly Murder of Dirty Pete by Eth Clifford, 1981.
Mary Rose Onetree is starting to think that her father really likes her younger sister, Jo-Beth, better than her. Her father seems to like Jo-Beth’s dramatic flights of fancy, and he likes to say things to make her laugh. Mary Rose, on the other hand, is the sensible, practical one, and her father keeps getting irritated with her advice, especially when she frequently turns out to be right.
On their latest car trip, going to visit their Grandmother Onetree on the West Coast, Mary Rose warns her father not to leave the main road (something that he loves to do because he’s a newspaper man and can’t help being curious), and he does so anyway. Mary Rose warns him that she can’t even find this little side road on the map, but when he sees the sign that says, “Inn of the Whispering Ghost on Skull Valley Road. Two miles right at the first crossroad ahead,” nothing can stop him from going further to investigate.
Harry Onetree and the girls find a ghost town with a hotel, an opera house, and several other buildings. Although Harry only means to look around for a little while, he forgets to set his parking brake (something else Mary Rose warns him about, which he ignores), and their car rolls backward into a ditch. Since it’s getting dark, they’re stranded in the ghost town for the night. But, they’re not alone there.
They find some food in the hotel’s kitchen, and one of the chairs is warm, as if someone had just been sitting there. In an old newspaper at the hotel, they read about Sorehead Jones, who murdered the hotel owner, Dirty Pete, back in 1905 in order to get his hidden treasure of gold. But, Dirty Pete wounded Sorehead before his death, and Sorehead died shortly after, swearing that he’d seen the ghost of Dirty Pete. Supposedly, Sorehead is also a ghost who wanders through the town whispering, “Where is the gold?”
Could the ghost be the mysterious person in the hotel? But, why would a ghost need food? Then, Harry realizes something about the town that changes everything, but they still need to confront the whispering ghost before they can leave.
The solution to this one concerns the difference between fantasy and reality, and the lengths that someone might go to in order to make someone else happy. Mary Rose also comes to realize how much her father really loves her.
This is part of the Mary Rose and Jo-Beth Mysteries series. It is available to borrow and read for free online through Internet Archive.
Scared Silly by Eth Clifford, 1988.
While the Onetree family is visiting the museum, a pair of shoes that once belonged to a Chinese emperor disappears. Like the two Onetree sisters, Gus considers himself the sensible brother and doesn’t take Razendale, the dreamier sibling, very seriously. He thinks Razendale ran off with the shoes as a prank. But, Erik, who seems more sensible than either of his uncles, says that they can’t just accuse him without proof. Gus provides them with an invention that could settle the whole matter, but that depends on whether or not they can trust Gus.
Just Tell Me When We’re Dead! by Eth Clifford, 1983.
The first place he goes is to an island in the middle of the lake near his house. The island has campgrounds and an amusement park, which is now closed for the season. Mary Rose and Jo-Beth, realizing where Jeff has gone, follow him there. But, the children are not alone on the island. When Jeff is captured by two criminals who are looking for loot that they stashed on the island years before, he has to keep his wits about him to find a way to summon help. Meanwhile, Mary Rose and Jo-Beth have no idea what they’ve just walked into.

Be a Perfect Person in Just Three Days! by Stephen Manes, 1982.

This is the last of the four books I have in this
Triple Trouble in Hollywood by Michael J. Pellowski, 1989.
Sandi doesn’t want to do it because it would be dishonest, but Randi and Mandy talk her into it. It’s partly to help Mandy, partly to get back at Tara for her rotten attitude, and partly for the chance to meet the heartthrob Judd Morrison who will also be in the commercial. Of course, as is always the case when the girls switch places, nothing goes as planned. But, to the girls’ surprise, their younger brother Teddy helps to make things better in the end.
Triple Trouble by Michael J. Pellowski, 1988.
But, Mandy’s snobbish attitude rubs Randi and Sandi the wrong way. Mandy doesn’t want to do anything because she might get dirty or break a nail, and she keeps bragging about how grown up she is compared with her not-much-younger cousins. The twins argue with their cousin, and they play tricks on each other. When Mandy takes advantage of acting skills and her similar appearance to the other girls to try spending time with a boy they like by pretending to be them, Randi and Sandi decide it’s the last straw! They decide to show Mandy that playacting is a game that three can play at.
But, everything goes wrong when Randi’s coach talks to her teacher about the championship game, and it turns out that her teacher is secretly a soccer fan. When Sandi arrives for the tutoring session and the teacher and coach tell her the happy news that “Randi” can play in the championship game, Sandi has no time to tell Randi about it and switch places with her again. Will their hoax be exposed? Will the girls be able to switch places again in time to save the championship?
