To encourage a greater distance travelled between cultural sites, making distance a condition of the experience gained by a player, we could include this table:
|This counts as 20 miles per hex.|
Thus, a party of characters reaching for the easiest fruit, moving from close town to close town, could still benefit from week to week investigation, but if they chose to move great distances before touring again, they would gain more per week. This, of course, would not increase the total amount of experience available from a cultural center, but it would increase the speed with which cultural gains were made. That would incorporate a cultural shock into the learning experience.
As a second feature, we could use this list of places from Wikipedia (making your own up, of course, if it is your originally created world) as a guideline for pilgrimage sites. The adjustment here would be to double or perhaps triple the amount of experience-gaining potential for true believers of the given faith. Therefore, though Rome in my game is not the largest of cities in Europe (it has 313,786 people in my world), by giving it three times the potential experience gain, rather than having a maximum experience base gain of 3,137 x.p., it would have 9,413; and if persons were to travel 100 hexes to reach it, or 2,000 miles, that would be increased further to 16,944. Though it would take a total of 94 weeks and a day to gain it all.
That would include time looking at art, visiting churches, attending ceremonies and festivals, reading in libraries or conversations with religious leaders and scholars, etcetera.
Would players really want to do it, though? Would they be willing to sacrifice a year of life in order to gain a "safe" boost of experience? Or would they rather just adventure. On the whole, I see these rules being something that low-levels, up to 5th say, may jump at, but in which those higher than 6th would probably lose interest.