Very importantly do not forget to have water on the course and afterward, the presence or absence of water afterward can make or break a race so make sure there is plenty of water afterward. You should have a water stop on the course at least every 2 or 3 miles. There is usually fruit and snacks but this depends on what you can get donated. Some races have door prizes, which are donated by local merchants. It is nice to have your race and awards ceremony at a public park where there are bathrooms if not you may have to arrange to have Porta Potties delivered. If it rains it would be nice to have a picnic shelter. Be sure to check with your city recreation department on this.