Know-How Exchange : Advertising/PR

Talk with local pet shops, pet hotels, trimming places etc.
- ask if you can place a poster, maybe even get them to allocate some business to your cause on a specific day

Talk with local shops and supermarkets selling pet food
- ask if you can place a poster, maybe even get them to allocate some business to your cause on a specific day

Create a YouTube channel with fellow walkers and their favorite animal, even if they are not directly concerned with your cause - then send links to all local press with online presence suggesting they mention your cause and your walk

Create the event on Facebook (in spite of you glitz) LinkedIn, Foursquare, Plancast, Yelp, MeetUp and invite everybody you already have on your email list to each one of these, urging them to attend

Give away T-Shirts to people who sign up with the date, name and cause in BOLD

Mikael
B2B Marketing

Dog parks. Pet shops. Veterinarian offices. Animal shelters.

Have people submit photos of their pets, with winning photo (that somehow ties in with your non-profit) gets a prize.

Day of event - dress up like your pet contest.

Instead of arrows to indicate the path (like:https://www.coursemarking.com/), create a pay print stencil and mark the path (up to a couple of weeks before) using marking spray chalk to attract interest.

I am with the others. On getting the word out, posters at pet related locations (pet stores, dog parks, etc.) would be effective. Posters for their windows, ask them to send word out to their customer base (through emails or Facebook or however they ,may communicate with their customers), etc.

At this late date, a Facebook page for you may not help much. Take a while for enough volume of people to "like" the page - perhaps not enough time. So the benefit of friends of friends seeing this may be limited. But do set up0 the facebook page. And maybe just list the event as all day and put the time in the text, if you are having trouble with times.