Glad you chose a Fenland for your map
Kits would be awesome, if you make them extra high res then I'll make use of them in my app and you can zoom into the parts of a castle further. I was trying to do similar with my thatched cottages thread in the tut section. I think I should expand that and have more cottages and do them all with several flavors of tiled roofs also. I have a few castle bits but its not enough to make extensive castles. I have a lot of castle reference photos tho from my visits.
No prob ill get you some in due course. I have the region in pretty high res 3D and can zoom in and recalc more detailed areas. Let me know exactly which bits you want. Take heed of the scale. I expect that castle would be a few pixels at most of the main map.
Yes I expect that the road is not on the actual ridge but just below. The dots connecting Fenridge to Nortonspire show it to one side of the ridgeline. In actual fact the scale is so high here that once blown up a lot you will see how it would weave about a bit. I would think that your right about exposing yourself on the ridge to winged creatures and also the elements. It might get real windy up there.
It's mostly continuous I would think. You get cliffs in Karst areas but they tend to erode very quickly. You know in LOTR film where Aragorn, Gimli and Legolas run across the hills before they meet the ROhan Riders. Thats the sort of landscape. Probably some ridges and small cliffs with scree. Mostly short rough grass - windswept etc. Scottish highlands kind of feel to it.
This is probably less true I think. The reason all of the towns are castles and forts and sit on the upper regions is that most of the fen land is marshy, not very easily traveled and full of monsters - notably Lizard Men who can traverse it much better. The merchants travel across the roads getting harried by the Lizard Men and so take large mercenary escorts. The water in the fens is probably not all that fit to drink. There would be springs all over the area about half way down the hills at the forest line which feed the marsh and lakes from where water can be taken. All of the forts and castles need to provide water catchers or have wells or take fortified wagons to the springs to fill up. Wells are probably not viable when villages are on the tops of ridges or peaks tho.
Me - oh I'm more of a cartographer then a historian I'll leave that to the bards...
Pic attached has a 10 mile grid on it.