I have organised a 'fun run' this year and it was great! Weather was perfect, nearly 40 people turned up, it was a lot of work but great fun. I am definitely doing another one.
All organised/advertised on Facebook and involved running in a local nature reserve. We asked for donations to go to the volunteers who maintain the reserve.
I did a careful risk assessment and asked someone who had never been to the venue to run around and point out potential hazards. This is important as I am so used to the route I will not necessarily see obvious problems.
I would suggest that you get people who are familiar with this entry road what their opinion is; runners and non-runners. Remember that a hazard is a problem that a 'reasonable person' would consider a hazard.
Also remember that the Police are not unapproachable! Talk to them! But getting them involved adds huge complexity to something that can become surprisingly complex.
If this is a big event then talk to a local running club? I am sure they would love to have help with their club event and this would be a great learning experience for you?
will i progress faster doing these very slow runs?
If you get a chance have a look at the 'MAF method' I don't fully endorse all of what he says but this is a quote from the Dr Phil,
"We live in a quick-fix society. Everyone is looking for that single, magical diet or miracle workout plan that will change their lives overnight. But that’s a fiction, a false promise—and it’s exactly the one that all the health and fitness magazines love to promise their readers"
But his philosophy is that we should always regulate our pace to ensure we are fit to run again in our next session. So; by cutting out the 'down time' caused by injury and illness (that will always follow overtraining), you will progress better and more consistently.