Yes I already thought having ditches would be difficult, but remember that they don't need to be filled with water. I hope you can add some on the sides of these main (country) roads. The Netherlands are famous for their ditches ;D
Good to hear that the farmhouses can be entered. Also nice to hear there's a river (although I can't imagine how someone could do a holland map without a river
)
I'm looking forward to this one.
Also on farms;
Most farms have a line of (high) trees around them (most of the times one line on either side of the farm terrain). This is because the farm's skeleton is made of the wood of those trees. The farmer plants these trees around his farm, so his son can use these trees to build his farm when he's old enough. (at least that's what they used to be for in the old days). Remember this when placing farms on your island. And place a lot of fences around the farmfields. Practicly avery field has a fence around it. (I'm not sure if you can use a fence that's in the game already, so you might want to consider making one yourself; just a few poles with two lines of barbwire. It would be great if you can crawl under the barb wire. Using the chickenwire fence that's in the game, you can't cross it as a soldier.)