How about like camps, a player can set up a market stall right outside of the city, it would make the world’s feel more alive and like a new world. Trading would be player to player and traveling merchants would actually have a purpose.
Maybe create a reason for them to pass between cities more often, remove iron from all mid level areas so merchants travel to low level areas to buy goods and transport them into cities, potions can only be crafted in high level zones, so if you don’t want to travel to the next city you need to buy from someone local who made the trip…
It would remove some of the strain of money going into the cities coffers as well.