I would tell you to get really, really smart on self-storage, mobile home parks, or something that can be run by a low-skilled employee and pretty hands-off. 

I have one Full Time Employee (and well paid) for every 10 properties we manage. 

My differing advice/thought is if you plan on being a doctor for most of your life, and your goal isn't to replace your income with real estate in the next couple of decades, sacrifice "projected returns" and do your homework on the risk for any deals you evaluate. 

You would still have time after the two year lease to evaluate and decide if you wanted to sell at that point.

I’ll definitely keep this in mind as I evaluate potential investments.

To succeed in hard money lending, know your local market well, value properties accurately, and carefully evaluate borrowers.

To properly renew a lease with a tenant, several tasks SHOULD be done:1) Evaluate the property to make sure tenant is taking care of it and you want them to stay.2) Do a market analysis of rental rates.3) Determine target rental increase amount4) We present all this to the tenant, as we assume they're looking at rental rates on Zillow, etc.5) We then ask the tenant what adjustment they think is fair and then negotiate rent amount and lease term (we always try to go for 2 years).6) New lease sent electronically to sign.All of this takes time, hence a Renewal Fee.

He explains how to evaluate and purchase.  

I have business overhead, operating expenses, employee expenses etc.

You also want to look at the property from an future equity position and evaluate the ARV.