I've been a little removed from the scene these days, but there are plenty of options depending on your style.  If you like upscale, head to Birmingham.  Young/fun/alternative/hipster, look into Ferndale and Royal Oak.  There are also plenty of bars, restaurants and nightlife downtown.  Lastly, there are also really nice options to the west in Novi, Northville and Plymouth.  

In terms of the hobby, I would suggest anchoring somewhere in Oakland county which is where the money is. (although I'm sure the downtown casinos may have opportunities too).  I see plenty of successful ladies book in Southfield due to its central location, but there's a wide mix of quality and competition there.  

Take a look at a few pages of the MI ad board and see where the top-rated visiting ladies typically locate.  As an example, Alexandra Kole and the City Girls girls seem to prefer Novi when they visit Detroit.

If you give me a little more specifics on what kind of girl you are / what kind of bars/restaurants/scene you like, I can make some specific recommendations.  Enjoy your visit if you come!