My concern is the cost to maintain the LLC - franchise fee, to file taxes fee, virtual office / P.O.

clean well maintained successful business paying regularly?

It's hard to know where to start, but I've begun getting the word out there that I may be interested in snapping up a property they are tired of maintaining/renting. 

Give your name and number and ask them to respond if they are interested in selling or maintaining the house to local and county codes  since it is clear that the house needs some maintenance. .I use the code approach to push the issue that their asset is declining and see if you can help - maybe they got cited already by the city - I find it generates more response than just a I BUY HOUSES card. good luck!

The ultimate goal is to purchase a multi family unit that I can live in and also maintain tenants.Any suggestions on good (modern) books would be appreciated.Thanks,Mike

Broken screens on windows, non maintained back yards, mail pilled up.

If you purchase correctly, in stable or growing areas, with fixed debt (as long as you can fix it), maintain your asset, & achieve cash flow (not over leveraged) then you should be okay.  

I'd stay away from SFH, Apartments, Retail, Office, or any real estate with four walls you have to maintain. 

But for many people (who are not technically inclined), those solutions are a big challenge to implement and maintain.  

The economic and business climate support this process, and the social factors of our population of buyers lead to them maintaining the houses.