Well now you gotta get creative with towns lol. Can they be on an island away from the field?
Are the bridge objects only as long as the rivers they are over now or can they be combined to any length?
Well now I haven't thought of that before.

I'll look into it, that might be an added "feature" to a map.
Bridges can be combined into longer structures. have completed a new bridge that is twice as long as the original. It takes some time and a good 3D graphics program, I use Ac3d which is what Hitech used in developing AH3.