Aside from permits and zoning, what are some other considerations I should think about or issues you might have run into?

Best to work just outside of Nevada City/Grass Valley though from a permit cost and restriction perspective.

I’m curious as to some insight community may have with regard to how the investments can be negotiated using the resources of the company I own (i.e manpower, equipment, Managment and legalities (permits,etc) has at its disposal.

You should consider the permitting process wherever this is, because it's entirely likely that everything mechanical will end up having to go through a new permitting process more or less the same way as a new build.

The zone will tell you what residential uses are permitted on the property. 

 I'd suggest contacting the county code enforcement office (they issue building permits) and ask about the rules.

I am thinking perhaps lease the land and help the local tenants out with finding the financing, planning, permits and utilities.

@Pasquale Zingarella Ask the Planning Department if they have a Special Permit process or Variance process that you can go through to try and add the 5th unit.

And then the actual fixtures and touches are based on preference, but the bones should get in for about $11-12k after permits and drywall.

We had to rewire & replace ALL of ours to meet code & get the permits signed off.