To me it is simple.

It also is worth approximately $140k more than my property is currently worth.My question: when evaluating renovations, is the math as simple as (Additional rent expected per month due to renovation * 12 months/yr)/total cost of renovation = ROI.

I'd appreciate if you could expound on your thought @JohnWarren  One simple explanation is that 1-4 units considered in Residential category.

It actually IS as simple as calling them and asking if they would like to sell, but you need to say it better than that.

Plenty of SFHs that are simple vacation homes for families getting out of the city and I would bet that will continue to be the case.

For appealing appraisal, the easiest way is absurd adjustments (and adjustments are often absurd: $10k for a BR when simple query of average 2br vs 3br sold will show value of that extra BR on average, same for bathrooms, etc).  

Tried a simple Google search but was surprised at how thin the options seemed to be.

Which is why I was surprised to receive this response: "That would be a good question for your CPA" when I asked a simple question this tax season.

I also recommend building some simple marketing materials.

(Note: Advertising can be word-of-mouth advertising or something as simple as a “FOR RENT” sign with a contact number posted on the property.