This is not directly tied to the production of the Princess of the Red Planet adventure, but this is a supplement for Warriors of the Red Planet and could be useful for that adventure.
Some time ago I posted previews of a deck of cards for the Beasties OSR monster books. I batted around the format back and forth, distilling the essential information and putting it into a useful poker card layout. After much discussion on the ODD74 board this is where it is at.
It will take some time to color all the beasties, and there are several creatures I didn't draw in the book that will need to be illustrated. How would this be useful in Princess of the Red Planet? Now many of these creatures do not appear in the original novel, but the referee is free to use whatever will make the adventure more exciting for their group. Each chapter in the adventure is divided into these sections: By the Book for those strict purists, Barsoom for a specifically Mars campaign, and a Sandbox section that is for a wider Sword & Planet style campaign that is a kitchen sink for the referee to use at will. But more on that later when I get into the individual adventure previews.