I'm doing the same kind of thing. It's our "creative" project of the year. And I know what you mean, it's tricky to make a quick game. But it can be done! Have you all seen the Ludum Dare 24 hour game competition? Great stuff.
I had some fun ideas. It's not too hard, I'd just program in random "events" like other boats, islands, things from the book etc.
@WarHampster: Y'know I like that, a quick art game on some book could work...
EDIT:
This is it guys. This has to be my project.
...I love my Huck sprite!
EDIT 2: Changed sprites just a bit, now Jim is taller.
I should post this game here if/when it's done.