Race concept
The second thing to consider is your audience. That might be tied to your goal. But you need to identify who will be running in your race. Your runners are the most important Race Pillar (Runners/Sponsors/Staff & Volunteers), since there would be no need for a race without runners. Is your race going to target local runners? If so, what types of races are popular or maybe, what race would be popular but is missing in your area. If you can fill a void in the race schedule and you have an audience that wants that type of race, then you have the seeds for success. Or do you want to start a kind of race that isn't in your area and there is not a large group in your area running this type of race? It's much more difficult, but the rewards can be great. When I started the Destin Beach Ultras, I did it because there were no ultras within several hours of my house, very few in the whole state, and a relatively small amount in the Southeast US. Now, 7 years later, we have a great local ultra running community and new ultra events popping up all the time so this target is constantly shifting.
The Course
Some areas that are easier to setup up than others: city parks, city running/jogging/biking paths, trails, beaches. Using any of these will greatly reduce your amount of work. You increase difficulty as you start crossing roads and then your highest level of difficulty will be closing major roads. If you are going to close major roads, you will need to check with local authorities on the process for doing this. If it is a city street, it may be as simple as creating a power point for local law enforcement and meeting with them to explain it. If you are closing a state highway, as we did for the Destin Marathon, the state required a traffic management plan developed by a certified traffic engineer. This document, for only 6 miles of road, cost of $20,000. I'm guessing a few of you just now decided on the closed trail option!
I would suggest sitting down with your local running friends and coming up with a few options to submit to the local authorities in case there is a conflict or problem with your first option.Also, be sure you think through your options from the view point of the local authorities and ensure that you address areas they might think are an issue upfront in your presentation. I like to use Google Earth or Google Maps to plot out initial course ideas. With Google Maps you can just right click on a point and click measure distance. Then you can plot the distance of your proposed course. NOT all races have to be standard distances- we put on a 3.3 mile race (instead of 3.1 mile/5K) to remember some local Airmen killed in a plane crash with the call sign Ratchet 33.
Creating a race concept and plotting out the course is one of the most fun parts of race directing. This is where you get to use your creativity and make something that fits your personality and the direction you want to take your event. The world is full of standard 5Ks, come up with a concept that either livens up the 5K or create something totally new.