Well try to make it to the next meet @Peter Tomeczko We would love to have you.  

If you rent out any property for 14 days or less in total for the year, you don’t have to report the income or pay any tax on the income (this is known as the “Augusta Rule,”).

Social media can be a powerful tool, and then good old-fashioned door knocking for listings is a great way to drum up business as well! 

Major dry rot/pest issues or perhaps knob and tube wiring would make me hesitant as well. 

Is there a program or software that allows you to easily observe all the properties in your portfolio, as well as their details?

Would love to learn from you all experts here and contribute in the discussion as well.

This is what I'm thinking as well.

Also, if you are open to other asset classes, you might take a look at small commercial spaces in some of the outlying communities as well as light industrial spaces that need some TLC. 

In short, all of the people that you need on your "team" that I have used personally, as well as, many of my clients for many years.

You can let them know well in advance rent would go up to $X or simply ask to have the unit vacant at closing as it will be close to the end of their lease.