I read The Castle in the Attic. I also read Loch. Loch was excellent. The Castle in the Attic was also an excellent book. Loch is by Paul Zindel. The Castle in the Attic is by Elizabeth Winthrop.
Loch is about a herd of prehistoric sea monsters called plesiosaurs. The plesiosaurs are endangered because a man named Cavenger is trying to kill the herd and get rich by taking them into the museum. Three kids are trying to stop them - Sarah, Loch and Zaidee. Only their father knows how to open the trap, called a grid, that holds the sea monsters in the lake. I definitely recommend this book.
Castle in the Attic is about a portal to a medieval world where there is a wizard waiting for battle, and a dragon that's guarding the gates. In front of the portal there is a finger-high knight called the Silver Knight who used to own the castle that the wizard has taken over. His father was the king who was killed by the wizard. The Silver Knight returns with a boy to defeat the wizard. Before they get out of the forest, they see many images of food and stuff they love but this is only to get them off the trail. The rest of this book you should read yourself, but I highly recommend it.