I live at the end of the world in south Texas. There are no train shows. I am sure there are some train guys but there is not much way to know. In the northeast apparently every third house has a layout and every weekend there is a meet within walking distance. If the TCA meets here were actually happening, the closest would be 250 miles. I admit, this is Texas and that is not considered very far for a drive.
99% of my buying is on ebay unless it is for something new then we probably all go to the same list of dealers.
I guess my point is that I do not have the same selection options that the midwest and northeast collectors have.....but I get to live in Texas....