I'd put this mailbox out on a table at the reception to see what people write.except my mailbox would be much cuter.and painted to match ;) mighttt even use it as the official mailbox of my first home!
Perhaps purchase a polaroid camera and try this idea (instead of a photobooth or as a wedding favor). DIY Wedding Table Decoration Ideas - Novel Guest Book - Click Pic for 46 Easy DIY Wedding Decorations
Instead of a guest book, try a polaroid scrapbook. Make sure the polaroid camera has plenty of film. Wedding guest can strike a pose then leave their photo on the guest book, together with their short message for the couple. INSTEAD OF GUESTBOOK IDEA
Ways to save money=no programs My wedding planner gave me this idea. She said that people spend so much money on programs and of them end up being trash IF people take them at all. Tell your ushers to have people check it out before seating them.