The Mystery at Point Bonita - M. C. Tillson - Bog

A puzzle? A contest? A treasure hunt? How about all of the above!
Everyone wants to help win the "Mystery Word Contest," but first they have to find the clues at three San Francisco Bay Area lighthouses. And they have to find those clues before the other person in the contest, Dr. Frank Lee Boring-who seems to be following them everywhere they go!
After sending Dr. Boring off on a wild goose chase, Sam and Becky, with Mom and Dad and their cousins, Jeremy and Mikey, drive across the Golden Gate Bridge and into the Marin Headlands. They soon arrive at Point Bonita, but getting to the lighthouse is whole other story.
Even with help from an unexpected source, it's going to take everyone working together to figure out the mystery at Point Bonita.