Here is a new Neighbourhood Terrain, inspired by discussion on 
it was intended to be a somewhat mediaeval place, with space for a large hilltop
monastery, and some sparse villagey areas.
Here is the SimCity 4 view so you can see the overall layout.
In Sims 2
In this shot you can see I put in a few largish blocks of building land for the monastery - actually it will be a convent in my game, Sant' Clara.
Interesting that the trees I put in in Godmode in SimCity 4 seem to appear in bands in Sims2. This might be an issue if you don't want the pink flowering trees or cactus! (Of course you have more deciduous trees to add in Sims 2 neighbourhood Decoration). If you don't like them, they are easy to remove in the Neighbourhood Screen, one at a time, pick them up and delete.
Placidia has a Roman Road running North-South. Because of the variation in vegetation it looks like a warm temperate climate to me.
There are a couple of clearings suitable for villages. In the screenshot above it was set to Lush terrain when imported to Sims 2 - with NightLife it can be set to Dirt as well and looks like this picture below. Far more mediaeval to me - but then I agree with Terry Gilliam that the Middle Ages were mucky!
(Note to self - need some muddy mediaeval clothes....)
Stone piles at crossroads would be neighbourhood decoration - hmm. Maybe a witch's cottage or two as well....wonder if anyone has made a ducking stool?
Download Placidia (works for ALL versions of Sims 2, but remember you can only have dirt with NightLife or later EPs!