What about caravans. They can go amongst the city's, player can trade with them on the road if the dice roll says they are there. And can invest money in them every week dice roll decide did they get money from the investment random*investment/10. Or players can create caravan companies. X money for company Y money for caravan Z money for guards. You must pay guards and caravan master every week. Every week dice decide if caravan has made profit, was it attacked and if someone has died. This can be a good money sink
