Our contest coordinator here in District X is good about sending out a tentative schedule based on the previous year, and those of us within a fairly small radius coordinate among ourselves.

Your contest coordinator should have done the same thing and at least alerted you guys,

A little late to this.  Here is a copy and paste from the "Contest and Directors Guide", pdf 322. 

PROTECTED DRAWING AREA
The base on which the system is built is that of protected drawing area. Actually, this should be interpreted as modeler population, but this is very difficult to use, even in the most general sense. Only after years of experience in a certain district can a coordinator develop a feel for who flies what and lives where. It is hoped that those coordinators who have developed this information will use it rather than rough area measure, which we propose here.
In general, on the same date, there should be at least the following distances separating contests:
Class A, C;     100 miles
Class AA;       300 miles
Class AAA or AAAA   450 miles
(These distances should be scaled down in high-population-density areas and should be scaled up in low-population areas.)

If they were all Class C events, 100 miles isn't that far between some clubs.  Issues or questions contact your Contest Coordinator to find out how he is doing it.  If all else fails contact your District VP .

Getting to know who your event coordinator is will permit you to learn who's hysterically historical event gets protected so you are not surprised by no one but the usual crew showing up. This is extremely important if you are wanting to make $.

This brings me to the next element of your event. Who's paying the bill? Sponsors within the hobby industry these days are good for glue, an occasional hat, T-shirt, spinner, or in the case of a scale contest Frankie's good for a walk around the walls in his shop and shipping a scale contest a nice box of goodies...and of course Pacer products.

Seriously, who's paying the bill?

I hinted relative to a scale event. Don't count on a lot from manufacturer's late in the year. They plan their promotional budget six to ten months in advance. I don't care if your event is in October...send your "written" formal inquiry in a personal manner to the owner of the manufacturer/distributor no later than November prior to your event. They budget spending money... 

1. In the letter explain in four sentences what segment of the hobby you are attracting.
2. Explain the draw at previous event of this same type at "your" field.
3. List the class or number of awards/prizes you plan to give participants.
4. Provide the estimated (truth) number of spectators attending the event in previous years.

You didn't see anything about how the event was to be paid for did you..... That's because you have to work up a realistic budget...not kinda sorta throw the event and its budget together in the hope "they will come"...especially spectators. Ah,the core of financial sponsorship lies in the demographic of your spectator. Potential $ sponsor is going to "see" the return on their investment in your toy airplane gathering. (Think about that a moment)

After working up an event budget, deciding on what awards/prizes you would "like" to be able to present to pilots for whatever...go for the gold...its in your back yard.

Go see your local Economic Development Council. Every community has one, typically comprised of "old money" with long tenure in your immediate location and even county wide in rural areas. If you are in a metro area this can be successful if you have a club meeting to find out who in your club knows whom would be an inside straight to your Economic Development Council. Who's the elder club member with the longest tenure? Acquiring $3k to $4k is a common figure the EDC will entertain...plus advertising which comes along with it free of charge...

County Commissioners need to justify their elected positions witnessing and "helping" community organizations...especially where family recreational activities are concerned. They can go a long long way toward contributing to the physical attributes of your flying location and amenities at it. There is always public land in need of improvement and baby sitting.

Last and definitely not least increase your participation and investment in your Boy Scouts, ROTC, Civil Air Patrol, local airport, and fire/life saving crews.

Your local Economic Development Council has a HUGE market budget if works with to attract family oriented businesses to your town and county. Your EDC works with the realtors, developers, and contractors within your community. They are all competing for the back pocket of "your spectator".

Bomber Field draws between 6k to 8k spectators with two major events each year. An event the magnitude of a USSMA Qualifier, Giant Scale Air Racing, Golden Age Racing, WWI and WWII scale events can be 90% paid for outside the hobby industry.

Its not difficult to do...a small group of club members simply have to plan how your EDC and other organizations can be approached...by your event "team"