My grandparents are selling their 70 acre ranch in Vacaville CA. It is uninsurable as the state requires a new bridge and public access road to be constructed to their property. My thought is to make it a vineyard, bed and breakfast, winery with tasting room, possible on site restaurant, etc. Access to existing public roads would require purchase of easements from surrounding property owners as the state will Not allow them to rebuild the existing bridge in its current location. Where would I begin? Who would I consult first to determine the scope of this project? Then how would I determine whether the whole object is worth pursuing or If it's better simply sell the whole thing as is?

I would be surprised if the state can force your parents into 'not replacing' an existing bridge which would isolate them from public access.  I would start with a Solano county land use attorney and make sure you understand the situation.  You can try Yelp or Avvo, to find a land use attorney, but buyer beware.  

Assuming you do need new infrastructure, you would speak with a local civil engineer to help you navigate the process and the requirements.  A local architect could help you understand allowed uses (vineyard, winery, etc.) given zoning.  

Again, I would really be surprised if the state can really back them into a 'forced' easement purchase from neighbors.  Elderly farmers are pretty sympathetic actors in the eyes of real estate law...

@Collette Douglas

Hello, 

May I ask how this turned out for you?  I have a family member in a similar position. 

Thanks for your time and effort.

Bill