The charter-stones have become exclusive for larger villages. The rest of the world do not have the access to them. Therefore, the trade is quite stale, since the majority of the potential buyers belong to the people who are local resources deprived. Therefore, I suggest to do the next:
1. Charter-stones can be built in any village for the W8 ingredients
2. Rock crystals are optional to be built in, like sketches in banners. However, the charter-stones that have rock crystals built in should not consume any travel weariness.
Therefore, the population will be able to socialize and visit trade ports and inns. At the same time, rock crystals will still be demanded, since travel wearness is very annoying and it takes 100+ charisma for 1 jump trough the map.