I've helped with
a fall offseason event for going on seven years.
1. Timing: It's tricky - you want to make it early enough in the year so teams can build off the experience, but late enough so that teams have had a chance to form and coordinate themselves. Our event is always the third Saturday in October - that makes it easy for teams to plan, and for our administrators to schedule.
2. Location: Anecdotally, it is better to have the event in a single, large area that can house the field, spectators, and pits together.
3. Parking: The venue should have ample parking for teams, spectators, media, load-in/load-out, field setup and teardown.
4. Food: Several schools of thought on this one. If done properly, this will be your main moneymaker. Some events prepare their own food (parents bring in hot dogs, chili, bbq, popcorn, vending-sized quantities of chips, candies, drinks, etc.); some events "cater" (area businesses either donate or heavily discount their food for the event to resell out of a concession booth); last year we had food trucks provide lunch at our event while we had drinks and snacks. No matter what way you do it, make sure there are options for any dietary requirements you may encounter.
5. Volunteers: They need to feel welcomed, valued, and respected. Have a volunteer room stocked with snacks, drinks, COFFEE, and a place to relax a bit. Fall offseason events are great for creating a new volunteer base for your community, and retaining existing volunteers. Make sure all people involved are well-trained and supported throughout the event.
6. Teams: Find out what your teams' strengths, weaknesses, and needs are. Play to their strengths, support their weaknesses, and provide for their needs if possible.
7. Media: This is a great opportunity to showcase some really awesome accomplishments from area high school students and their mentors. These events have great local and regional appeal - make sure local media realizes that.
8. Continuing Ed: Colleges and universities would be very interested in what amounts to a captive audience of the best and brightest of the community.
9. Delegate: Area teams and people would love to help you and support your efforts; all you need do is ask.
10. Setup: As you set up the field the night before, leave time for extensive testing. Run through matches with six robots to ensure connectivity etc. This will take more time than you expect, but it's better to make sure everything is to spec before the event actually begins.
Please PM me if you have additional questions. I'm happy to help with my past experiences.