Are you thinking of a simple 12-page (with a cover page) calendar?
Run the comp, best 12 pics get entered, make something like the top-of-web-page logo for the front page.
How big do you want to do each section? How big do you want the days? Do you want to put school holidays in? Which day of the week do you want to start on?
I think the idea's brilliant. In fact, you could use some of the photos from this lot. Original quality would be required, so the printing looks better. Whoever's responsible for putting it together should also ensure that number plates are replaced by "NAVARA".