Could be travelling nurses near med centers.  

It's not just for travel nurses.

We will be absentee investor/owners but of course will travel to the markets when necessary. 2) We are particularly interested in C-grade homes/condos located in B-grade neighbourhoods. 

I HAVE considered STRs as well as Med-Term rentals (travelling pros) and am not opposed to them, but it's an area of real estate I know far less about. 

Set your travel boundries first... local, regional, state wide, multi state, etc. 

So I have some knowledge about what you are contemplating... but even with 37 doors,  I wouldn't even start to think about 1,000 units or something crazy like that without significant external resources and partners, and even then you are probably talking about a syndication deal with lots of investors.  

I'll check on the rent, it would likely be medium term as it's near a hospital and several schools for students/traveling nurses etc.

The money is just the “fun tickets” and a measure of success in solid investing, but what I really love about real estate investing is the freedom it provides – money, time to spend with family and to travel.

Same here...I wanted to go but am already traveling a lot this coming week.

Prolonged enthusiasm can be exhausting (failed offers, tours, travel) one way to remain engaged is to stay connected and in constant communication.