April 9 is great, Lane. I also agree with Tom-- Make a recommendation, and let people book it themselves.
As far as "gauging general interest" and the like: I did Corn Daze twice. The weekend was lousy (a week or two after Carlisle) and the location was generally not a tourist destination. The second year we had about 8 cars, if memory serves. If you just pick a venue close to your home, pick a date, and roll with it-- if nobody shows up, you're out nothing except your time. Corn Daze 3 fell apart when my buddy Bob moved to FL, and I had a scheduling conflict.
The point is, I'd recommend just picking something and sticking with it. The Tail of the Dragon thing a couple of years ago (the one that was cancelled): I never popped my head up as a "yes", even though I wanted to go, in no small part because the weekend and the venue kept bouncing around. People need to plan. Give them something to sell to their wives.
Terry Nuckels has done the "Tour de Hoe" every year for half a dozen years. He picks a weekend when he wants to go, and he goes. One year, it was just him and his car on Indian Hill Road, etc. This year it seemed like half the world converged on Lake Tahoe. Either way, he had a good time, and got to spend the day in his car.
If you pick April 9 in Savanna (or Charleston... I'm not sure where that landed), then grab the bull by the horns and name it as the weekend. Flog it hard here. If you have to cancel, make sure you do it at least a month out.
Build it, and they will come.