If you really don't want to go to monger bars, just invest a few hundred baht in a Fodors/Frommers/whatever type of guide book that is aimed at the "normal" tourist and only go to the places they recommend...and then if you end up at the wrong kind of place you can say, "but it was in the guide book" and not look like your mongering self, but let's face it, eventually you will end up near to one of your favorite bars and you will suggest just taking a look inside, and when you go inside you are going to be greeted warmly and enthusiastically by some bar girl that you may or may not remember but who calls you by your first name and the jig will be up.
Not that this sort of thing has ever happened to me.
