How to make the non Agent sale easier..

[Mark Fedorov]

I have a duplex that I have owned for 22 years, I lived in there in the 90's I know it well, it is an easy place to manage but I have to sell it (my son is off to college next year). It has tenants, I have had one month of vacancy since 2012, I would prefer to sell it without an agent, however I worry that there will be dozens of investors wanting to walk through the place, disturbing my tenants, making them antsy and the investors then low ball or otherwise do not generate reasonable offers.

What is the best strategy for making sure the potential buyers are serious before letting them in? 

Lots of pictures on a web site?  As for proof of pre-qualification? Open house type tour?

Any advice is appreciated.

Mark