My four-year-old and I have read through the My Father’s Dragon trilogy three times in a row. We can’t find anything similar to match the enjoyment he gets from this series.

Some of the things I specifically love about it and would like in similar books: great sense of adventure without violence, written in non-simplified English, doesn't have anything scary in it, and long enough to really have to invest some time into it.

A lot of chapter books I've gotten since reading this have been written for young kids to read on their own and can usually be finished in a sitting or two. I'm looking for something longer that is not written to be read by a very young child.