I've never personally had anything to do with putting on an event but one of our group's member's SCV unit puts on a small local event so I have a little insight. It's a lot of work, he starts working on the next year's event immediately following the current event. Finding and keeping a good location for an event is the first challenge. There's insurance and security. You have to get the word out and do it early before the season starts so participants can plan which these days means having an internet presence. Then all the details like camping areas, porta potties, firewood, water, parking, ticket/registration sales if you a charging such. Concessions for the spectators and participants if you choose to have them. Have to have a solid plan of events. There's a bunch to it.