We took out a heloc from the SFH to get the money down for the duplex which we lived in one of the units.

I grew up just north of San Francisco and moved to Reno, NV to live and invest.

Many now getting back to live events.

But if the stock market crashes, I still have the rental income coming in to live off.

I will be living in one unit and renting the others out.

Looking at Redfin's data, it is appreciating over time (probably more than $15,600/year), but probably not as fast as other highly desirable neighborhoods in the Bay.I previously lived in this home before I moved and converted it into a rental property.

As long as the city does not hammer the builder with connection fees  ( or waives them would be best) I can see this working well as long as folks will pay that much to live there and of course Schools will dictate how well it will do long run.  

This is actually my Grandfather's property that I am trying to get him a monthly cashflow since he is now in an assisted living situation.

I currently live in Puerto Rico ( US territory).

If your lease agreement doesn't prohibit driving too fast in the residential area of the unit, you need to have a landlord attorney in your state look at the lease you're using, because driving too fast in a residential area may be a civil or criminal infraction or may even rise to the level of endangering the lives of others (neighbors).