Its annual STR rent is likely more than it would cost to rebuild the duplex (Peak rent is ~$350/unit per day = $700/day for the duplex, Minimum rent is $80/day per unit - it is rented virtually every day).The fear is San Diego STR regulations. 

An LLC may be the perfect route for one person while an S-Corp may be perfect for another.While on the surface, both are doing the same type of business, the facts and circumstances regarding their financial and tax goals, their other sources of income, their tolerance for regulation, their family status and their retirement goals may be vastly different, which would affect the type of entity that works best for them.Taxes are not a cookie cutter, one-size-fits-all topic.

Spent 3 months just researching our landlord tenant regulations.Most new investors don't bother to learn the regulations and usually end up on here after backing themselves into a corner.

Your state landlord regulations will usually cover death of a tenant however in this case the son is the lease holder not the mother, and as such nothing has changed for you or him.

What does your state landlord tenant regulations say regarding maintenance repairs.

Even if you're totally in compliance with all city codes and regulations, some zoning decisions allow for neighbor input.  

That a land mine field of regulations.

For instance West Virginia has a reciprocal agreement with Virginia....but will refuse to issue a license to a Virginia licensee that lives outside Virginia, even though no law or regulation states that they can or will do that.

Guidance memos, regulations, and enforcement policy as issued by the executive branch of the government (whether state or federal) as well as case law further expound on the law. 

My only concern now is to figure out the regulations for the historical places..