You could do it this way: add a building for merchants; they'll organize caravans and trade with other regions, cities, and villages (they'll simply travel off-map). After a while, they'll arrive with money or goods. These merchants can only be unlocked once you have good relations with the king (complete quests from kings).
#Add merchants travelling to your settlements to buy and sell
leaden pumice
spice merlin
Add merchants travelling to your settlements to buy and sell + Bandits attacking those merchants
fallen lodge
I partially agree with the merchant idea if you mean the caravan type; for bandits no - maybe if they are part of a questline or a quest; the same idea for a caravan only if it is of the once-a-year type and if its work like a herald that you need to do quests and or you need also to achieve a certain reputation in order to be able to buy special and rare items that you don't already have at regular vendors, because realistically why would anyone bother with a caravan when they can go to various bases and buy and sell
leaden pumice
I've changed my mind. You could do it this way: add a building for merchants; they'll organize caravans and trade with other regions, cities, and villages (they'll simply travel off-map). After a while, they'll arrive with money or goods. These merchants can only be unlocked once you have good relations with the king (complete quests from kings).