What should I be aware of, all else being equal (taxes, zoning issues, the area (possible crime, population decline, unemployment rate, economic vehicles, transportation hubs, etc.).

He is a millionaire and lives a middle to upper-middle-class lifestyle - he simply has no debt, no housing expense, and little transportation expense.

One of these is a bank that I've dealt with on previous projects and they didn't flinch (actually, they were rather excited to work with me on this) when I put the initial thumb-to-the-wind figures in front of them, I've got a couple well-placed contacts in the city's development/planning agency and will be speaking to them today as I'm also investigating the possibility of establishing a public transportation hub on-site as well.

(within subdivision,  parking spaces etc)o  Close to big employers and avoid those sensitive areas.o  Good schooling districts, easy access to public transportation etc.After some extensive research and to satisfy the above said points I have decided to acquire a land to build some rental units.   

I do have capital to pay cash for up to 1 or 2 properties, depending on price.Primary commercial properties i'm interested in are,Retail/small plazasOffice buildingsMedical BuildingsIndustrial spaces that relate to transportation ( such as semi truck yards/shop/parking)Also, these are the current websites i mostly use to search for properties, please let me know if there are any other. 

The reason Lawrenceville was able to come back is because it is self-sustaining with business and transportation.  

Section 8 rents are good in relation to the market prices, values are fairly stable, population is increasing and there is a strong rental market with good public transportation.

The excess is meant to cover typical family needs, such as food, transportation and so forth and is referred to as residual income.

you are basically meeting the 1% rule... very rough guideline monthly rents equal 1% or more of total cost so 1200 is 1% of 120,000 (assuming it doesn't need many repairs) ... any public transportation around you.  

Just open Google Maps and check the time it would take you with public transportation from different areas.