This is generally the area which is bordered to the north by 295, the east by Ramsey St, to the west by 210, and BUS 401 to the south. 210 and Ramsey sort of form a “V” shape to the south and Country Club Dr. cuts through the middle (W to E).I have recently found several homes in this area which meet my criteria but they move quickly and I have not been able to get one of them as of yet.

I actually have seen several large homes for sale in Dorchester for a bit over 500 k, but looks like crime can be an issue.

I found a property I would like to purchase, but the thing is the man who owns this property is in declining health and is looking to get rid of 4 more properties with similar situations.

That may have health consequences for your residents years down the road(recent research shows.) 

Why not try to approach the owner and buy the property first, you cut out several steps and a lot of time that way and then there is no possibility of the owner bringing the loan current and leaving you stuck with a note which it appears you don't really want?

I am using the Rental Calculator (in Bigger Pockets) for a several unit purchase (SFR).

There are several ways to get in contact with these owners - I suggest mailing or calling owners to start out.

I assume that if I go through the real estate agent course and exam, that I’ll have several advantages as a new Investor:1.

Had I known there was a tank I would have a) not purchased the property (I passed on several properties because I didn't want to deal with an oil tank) b) had the owners remove it at their expense or c) would have asked for a significantly discounted purchase price to account for the risk.

But if you have several applicants meeting your criterias just pick the one you met and felt he/she would be a good fit for your property.