Work with municipalities to get the list of all affordable deeded properties and the deeds to determine course of actions. The City or County could take up their right of first refusal to purchase. Or the current owner could be offereed an incentive to re-deed the units in perpetuity.
Identify non-profit entities to purchase the land and funding sources if first-right-of-refusal action is taken. This might include CSCDA in collaboration with a non-profit such as Burbank, Eden, SAHA, MidPen (for rentals) and North Bay Community Land Trust or Habitat for Humanity (for ownership); the Sonoma County Housing Fund. A project like this, between the City and Burbank Housing, recently resulted in the rescue of 18 units of deed-restricted units whose subsidy was expiring.