In a way it's hard to believe more of your dad's stories weren't made into movies, though considering most of the ones that were made weren't done well it's probably for the best.
I just started reading Off the Mangrove Coast. I've read the book before so I read the LT section first. I've heard the audio adaptation of Diamond of Jeru, but I haven't seen the movie. Looks like I'll have to get the DVD from eBay. It is sold out here on the LL website.
Speaking of Sam Elliott, I watched an episode of Hawaii Five-0 over the weekend from 1974 that had him as a guest star. He looked vaguely familiar, but I wouldn't have figured it out without knowing his distinctive voice. I'm used to him having gray or white hair with the big mustache. Obviously he was too young at the time to have gray hair, and he didn't have the mustache either. Was like a completely different guy.

Peter