You may have trouble finding this book, but it's a great read and the protagonist (William Hardt, a lawyer) goes on an inner journey and a physical journey (to an island in the South Pacific, where he meets a pidgin-English-speaking, funny, interesting yet primitive society of people).
It's called
One Big Damn Puzzler and it was written by John Harding. It's about 480 A5 pages, but it's easy to read because it's a good story and there are no
archaic words in it. I'm going to use it next year as a related text for Journeys, you may as well too! If you like it, that is...