Children's adventure book, cant find name, read somewhere between 2000-2010

[Jackson]

Good day,
I am trying to find the name of a book I loved when I was a child. I was about 8 years old when I read it, so it must have been published around or before 2008.
The book was about a boy who is having his family over for the family get together of some sort, and among the guests is his grandmother, who has a massive amount of hair. His grandmother usually sleeps in his bunkbed, so he moves to the top bunk when she's there. The boy is having trouble sleeping and looks over the side of the bunk at his grandmother on the bottom. She is already asleep, and the boy falls out of bed into her hair. The boy discovers a new world in his grandmother's hair, and has adventures in there that generally teach him to be appreciative of his family. I remember he meets an elf girl of some kind? She serves as a guide in this place. I also remember he visits a cafeteria in the new world, where he indulges on a lot of meat, because his family raised him to be vegetarian. He gets himself sick, and ends up taking joy in vegetables making him feel better.
I would so much appreciate anybody giving me guidance to what this book was, and thank you for taking the time to read this.

[Lobstergirl, au gratin]

Jackson, the group rules are at the top of the group's home page - please go over them.

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