Continuing...
There was the Mine, now lets wonder about... not sure what, offhand. Sec. Ah yes, a trading position. Sadly, much as I have liked it, the concept seems fraught with possible exploitation. Anyway..
-Like the mine, you find a location fit for a Trader. Now, this one here will again have a variety of possible map-types, with the already existing gas station of Gordons as an example. The physical details of the location can be discussed/debated/whatever, as it is not really the key point of the location, though I hope they'd still look cool, I am just trying not to get off track on that.
1. After discovering the Location, you need someone to use it. This could be done a few ways, I suppose. One is talking to bartenders. Why? They know people. Also people like caravan drivers, wandering traders (NPC and players both, technically), and a number of other sorts, they would know who would be interested in using the Location. Not all bartenders will be helpful in this, maybe even some giving... false information, taking your payment and not even giving you anything for it, or maybe even sending a hostile force there instead to claim it (which may work for some. Imagine a Raider outpost taking it over. A new place for Raider-joined players to go and trade without being shot, whilst others would be, such as in the normal Raider bases). So basically, after discovery you find a Bartender somewhere, bribe/coerce or talk your way into getting them to pass the word to a trader, who hopefully will show up Before the map has gone visible. He will spawn at some point, walk to his position and... well, thats about it. The point of doing it before it becomes visible is that Pks (Raiders, whatever) could kill him en route through the (remember: the locations are multiple-maps wide, split among several areas) map on his way to the actual trade outpost, thus ending the venture.
2. Similarly, instead of Bartenders, people could go to other cities and get Caravans sent there. Hub being an obvious place to start for this, with one of those caravan companies being who you talk to. Paying to have some caravans go by there, which has a trader naturally show up to make use of it. If you want a particular type of shop, you may have to use a Specific Caravan from a particular location. I.E: Want a trader who deals in medical, misc, and energy weapons, then you get a caravan sent from Frisco, which will most likely cost considerably more, and may even take more time before they get there due to their far-off area.
As always, ideas presented herein are fairly rough in draft and written on the spot using old and present ideas I have thought upon and wondered about for who knows how long.