I think paying off your primary makes sense if you are close to retirement, but not if you’re young, and not if you have a sub 6% interest-rate. 

After that you'll want to see what sub-market/zip code might make sense given the relative rent/price ratios.

So many folks are out here touting making millions with $0 down and you proved that even with all the due diligence and good investing sense, you have to be prepared and take risks that are proportioned to what you can withstand.

Something will come up that will make more sense. 

If the rate is reasonable then it may make sense to try to save fast to get to the 3.5% down payment on a double or triple - househacking may allow you to increase your savings rate and pay down that loan even faster.As for estimating costs, closing in NY factor at least 1% of the mortgage amount for tax, plus $1500-2000 for lawyer, title and fees, then the amount required by the bank for escrow will depend on the actual property taxes and insurance.

One of our biggest clients plans on building more up there and meeting another GC or two would certainly make sense.

It didn't make much sense to me.  

There is a place and time that it makes sense, but as long as you get any cashflow that first year, father's time will likely help you out after that as long as you have a quality product. 

It may not make sense for you, however.

Of course, this makes best sense if you can make an agreement with the seller before buying the note.