I am considering paying off the mortgage lump sum, which would avoid around $135K in interest payments and generate an additional $1,400 positive cash flow ($28.8K annually).

Is your DSCR ratio greater than 1-meaning are you cash flowing (according to the lender's criteria of mortgage, property taxes and insurance (and HOA) if applicable).

ive seen a lot of terrible advice from gurus so far, I can say I’m avoiding all of them.

Is your DSCR ratio greater than 1-meaning are you cash flowing (according to the lender's criteria of mortgage, property taxes and insurance (and HOA) if applicable).

When you're weighing investment options, think about things like employment growth, rental needs, empty property rates, and property taxes.

She does have good credit and has paid taxes for the last 3 years.

@Andrea Evans I think:Worst Part - Lots of pitfalls you can fall into if you do not know what to look for like buying and property taxes double, suburb rental license, buying a property with violations, not understanding the importance of lease documents, etc...Best Part - There is so many opportunistic corners or niches in the city and suburbs that most out of state people do not know about and out of state investors never get to cause they get caught looking at cap rates on the south side and in south burbs. 

He would tie in before the property line to avoid right of way permits and inspection. 

The only cost the deal needs to absorb that's relevant is the interest, and even that is really just the delta between the actual interest paid and the tax savings on that interest on your federal return. 

Seek advice from legal and tax professionals to establish the most suitable structure for your US investments.