The Aldens are volunteering at the local recycling center, where they find plenty of things that can be reused, including a pinata that Benny takes home. But when the center is vandalized, the Boxcar children have a mystery to solve. Is there treasure amidst the junk?

The Aldens investigate when the arrival of several suspicious characters in Greenfield coincides with a mystery involving a popular boy actor.

A family starts out on a one-day mountain climbing excursion that becomes very exciting. In fact, it becomes an adventure for the former "boxcar" family. They unearth some mysteries and have a fine time in the process.

The Alden family rents a houseboat to drift down the river, and encounters a mystery in the little towns along the river, involving a fast black car.

The Aldens are spending a week at Camp Seagull on beautiful Claw Island. But as soon as camp begins, they realize that someone is not playing fair. Everything begins to go wrong for the Aldens—they lose their luggage, Henry misplaces the camp flag, and the campers on the other team use one of Jessie's ideas to score points for themselves. Are some campers so desperate to win the Olympics that they are willing to cheat? The Boxcar Children

...

When the Alden children go camping on Blizzard Mountain, a place said to be inhabited by a ghost looking for buried treasure, they begin to think someone or something is trying to scare them off.