Not Hobbit related, but kid and book related: make sure you check out Project Gutenberg and Librevox. A lot of content. Sure, some browsing/wading but there are gems.

We had Thornton Burgess (Mother West Wind's Children) when I was about the age as yours. Later with my own young kids I used Burgess audio tapes for a long car journey and I think that was from Librevox.

The Hobbit was one of the first big books I read on my own as a kid though.