I can sit at a computer and invest in the stock market, but Real Estate requires leaving the house and hunting down deals, then putting in physical labor when the deal comes through.

Back up those emails onto a physical device.

I currently rent a room in NYC and would like to keep it for layover purposes, while the new property (in SC) serves as my primary residence.How often must I be physically present at the duplex, for it to qualify as my primary residence?

And are you physically going to each c rental and collecting rent every month and keeping tabs on your property yourself? 

And my biggest concern regarding foreclosure property is that they don't provide you with a access to physically see the property.

With that freedom, I can be more...... available and energetic to my wife and kids... philanthropic, more often (and more generous when I do it)... physically healthy (would train for a marathon right now if I had the time!)...

Ask where the physical tax bill is being mailed. 

s suggestion to contact the neighboring businesses - however, if he is a one-man shop, he might not have a physical office and work from home.Since 2017 returns have been filed, you probably can afford to wait a little longer.

@Durante KirbyFair enough, consider the value of known-knowns when it comes to your Mom's property vs the unknown unknowns that you get with buying other rental real estate even if you are physically close to it.  

There are exceptions for military members who qualify, according to HUD 4000.1 page 128:Borrowers who are military personnel, who cannot physically reside in a Property because they are on Active Duty, are still considered owner occupants and are eligible for maximum financing if a Family Member of the Borrower will occupy the subject Property as their Principal Residence, or the Borrower intends to occupy the subject Property upon discharge from military service.”So as long as you “intend” on living there you can use an FHA loan.