Did the original explicitly exclude trading post? The problem is if it indeed was intentional, that's the same way of doing it as if it was unintentional. Not mentioning it at all. And there are no shortage of fluff excuses to justify any missing rules.
Hmmm. Unless it specifically said “no access to the trading post” in the campaign text then I’d assume you could access it.
After all that’s the only way to get some decent equipment for some fighters.
Indeed.Pretty explicitly.