> basing a book around a role-playing campaign can lead to books which read just like they're based around role-playing campaigns...

Like Lord of the Rings and Star Wars?

Guilty pleasures, they are two webcomics that re-imagine those two works as role-playing campaigns. The Star Wars prequels actually make more sense that way.

http://www.darthsanddroids.net/

http://www.shamusyoung.com/twentysidedtale/?cat=14