They are not able to sustain a consistent organic flow of work for one reason or another.

As time goes on, more and more Landlords/Owners are getting hip to this model and will be more likely to give you a Lease, especially if you have some Real Estate experience and present yourself in a professional manner. 

That said, the projection still looks sustainable as foreign cash investors continue to value this area; add to that new investors from northern states with high tax burdens, and this continues to be a great real estate market. 

However, I could not sustain that long term just because my objectives are to make some side cash as I get some experience as well in relation to my time availability.

It sounds pretty hinky that they are not responding to your communication in a timely manner.

Something that can pay for itself in the long run and sustain keeping a unit open for yourselves?

This just can't be sustained for any length of time..  

He has only said “fees” in a generic manner and gave us no idea what those fees would entail.

The doors will cost $800 to replace.The lease says the following regarding maintenance of the grounds:"Tenant shall at all times, maintain the Property in a clean and sanitary manner including all equipment, appliances, furniture and furnishings therein and shall surrender the same, at termination hereof, in as good condition as received, normal wear and tear excepted.

In my opinion (take it with a grain of salt), the Hagerstown market is currently being purchased at a higher rate than is sustainable.