Leave end caps and taps so you can easily add on.  

However, asides from that we believe we are comfortable to add one extra investment property per year. 

Now add on a property is appreciating at 5% annually.

Hi @Conte Cuttino, just wanted to add one thing: the population within the Pittsburgh city limits is small (300k like you said), but the population of the greater Pittsburgh metro is 2.3 million.

No one can be on the roof or attach anything to the roof. ( This was after tenants were nailing x-mas lights across the entire roof)No changes can be made to the landscaping.Driveway or street parking only, not allowed anywhere else.Property is to be kept free and clear of clutter, if there is any issue for fire hazard, termites, rodents (etc. the lease lists more), then they can be required to remove whatever is listed in our notice as the problem.And one of my favorite add on's is: When notice is given to tenant for work/repairs to be done on the property, inside or outside, and landlord, or any contractor or vendor is denied access, or cannot access house or yard for any reason, then tenant will be charged a 65.00 fee.

Is there a specific add-on insurance I should purchase?

I will add one thing as I do not see it mentioned here.

That is the easier way to get started especially if you don't have a lot of funds for value add.  One

If you add one more unit you lose the other two. 

I know a guy in MA who you could add on FB and DM him, and he may be able to help.