The property alone is worth a million but is generating an estimated $250k/ yr with the ability to add 3 units on site and acquire an additional 13 acres.

Welcome to the site Keegan.

You will want to insure a number of things as an MTR landlord: your interest in the building itself (owner's policy), your contents (owner's policy), your interests if a renter or guest is hurt on-site (landlord policy), and possibly flood, wind, lost-income policies.

I used to use the biggerpockets analyzer but it was a pain to login to the BP site everytime. 

Not a book, but Bill Faeth has a lot of free, good content on his site and YouTube videos.

I'll take any and all advice any of you have, but the two things I'm looking for specifically are: what sites, services, and/or software you use and recommend for sceening and managing tenants? 

We also have infrastructure in place at a build site for a 3rd unit on property.

Also a good stand of teak about 14 years old.There are two house sites possible.  

Here is a link to Prosper since you're familiar with that site that explains what I'm referring to. https://www.prosper.com/plp/di... 

There is a web site that lists all the section 8 housing, so people might be also be looking there.