Do You like book Mountain Top Mystery (1990)?
I remember liking this one because it had fossils and hidden treasure and mountain climbing. As an adult though, it's a little weak, and I'm not quite sure where to place it in the timing, if it's a new summer, or the last days of summer after they get back from the light house, or nowhere. And then, just a little thing, the scaffolding is supposed to take three days to build, as everyone keeps saying, but somehow, in the midst of the snow and rain and finding David, wow, the construction is done in a day instead! Book magic!
—Erika