Other than that you'll face similar challenges as those who are investing long distance but not necessarily from abroad...Great way to mitigate risk in those situations is as follows.Don't buy in the roughest neighborhood in the urban core.

The landlord's mitigating the problem is what would be expected.

Because you purchased this as a mixed property (primary and investment) you can use the appropriate tax mitigation technique for each side. 

I know many people think it’s safer to do nothing however you don’t get anywhere very fast that way. risk is always present look to mitigate risk in everything that you do.

Hopefully you mitigate as much as possible but there is still risk.

And the triplex will also mitigate your vacancy risk as well.

A close look at the seller's management of the tenancies can mitigate some of the risks, but Massachusetts is notoriously tenant-friendly in its courts.

Aiming to start small while I learn the ropes and mitigate risk along the way.Any advice on how to get started (meet-up recommendations, reading suggestions, etc) is always welcome and desired. 

It's those maniacs that buy homes cash via quit claim deed off of craigslist that really get screwed.Make sure your property manager is a licensed real estate brokerage.Google Clayton Morris and/or Morris Invest for a cautionary tale of what not to do when buying turnkey real estateUnderstand you can not eliminate all risk, only mitigate it.

@Marcus JohnsonAs I said, I understand what the issues can be as I own a fair number of rentals and want to mitigate my risk as well.