Once I get through the first two levels with a char, I tend to not take that char back into them. I know the shortcuts, while they are still there, anyway, so I just go straight to Skull Port. Leaves the lower levels for the lower levels...
I've taken to wandering around in town with lower level chars as well, checking doors. Found a new opened one, but there was nothing worth mention in there. A few chests/crates etc that needed relieved of their content...I hope I don't find myself escorted there by the guard though...could be a bad deal.