Ask HN: Referrals for Private Businesses?

I run a small farm that I want to keep private. I do not want to sell to the public; instead, I want to cultivate a small group of loyal customers that participate in a CSA (community supported agriculture) program and enjoy some other perks (eg. stocked fishing ponds, miles of hiking trails, camp sites, music concerts, etc.).

Since I want to keep everything private, I am at a loss for how to find customers beyond a word-of-mouth referral scheme (e.g. 5% off your annual membership for every new member that you bring to us). While I think this would eventually work, I am not sure how to bootstrap that model.

I figure that someone here on HN been down this sort of road, as I feel it is not far off from the notion of finding local investors for a startup company that needs to remain in stealth mode.

Is there a good solution to my bootstrap problem, perhaps used by tech startups? (Is there an app for that?) Anyone solved this problem (perhaps without tech) in a way that I might want to consider and emulate?