ahhh im with ya.... its sounding like a very cool idea...
So it would be like "a big day out" but for rc cars?
One of our local tracks did something like that. There was a 1/1 4x4 show and shine day. so they setup a little crawler track that anyone could use, BYO rc cars
They used Facebook and notice boards to promote the event.
First things to start with would be...
How big is ur loacal rc community?
is there someone "in the know" that can help?
would it be done on private land?
who is liable for personal injuries?
then go nuts on planing