Non-traditions guest books: how to deal with the line?

I found a guestbook online that’s a coloring sheet, where each guest can pick someone to color in as themselves and sign their name and then you can frame it to hang on your wall after the wedding. I think this is a really cute idea and I’d really love to do it. My only hang up is the line—people will probably take a few minutes to find a character they like and color it in, so with nearly 200 guests I feel like putting the guestbook near the reception entrance would create a huge bottle neck and be a bad idea. However, I’m worried that if I DON’T put it near the entrance, people will miss it or forget to fill it out. I really want as many people as possible to fill it out so that I can have the finished product as a sweet reminder of the event on our wall in our future home. I’ve thought about asking someone to direct people towards it or carry it around to all the tables, or maybe have the MC direct people to fill it out on their way to the buffet line if we call up one table at a time. But I’m not totally sold on any of these options and would love some advice!