(Germany is UTC (GMT) +1, so it's already May 22 here and I'm allowed to roll again.)
This puts me on square 15: The Mountain Cabin -- read a book with a tree (or trees) on the cover, or that has a main character who is a father.
Louise Erdrich's The Plague of Doves has a tree on the cover and thus qualifies for this square.
Length: 313 pages
=> + $3 upon completion.