Aside from the Feds and State, the acquisition of public lands is often "facilitated" by non-profit groups such as Nature Conservancy, Trust for Public Lands, Sierra, and Audubon. In the end, where there is a will, there is usually a way. Let's establish the "will" first and then focus on the "way".
P.S. I do believe the Davis family has contributed, as I recall, to Nature Conservancy, so they should be familiar with the possibilities if approached.