Well, I've come up with a solution to the Movement issue.
Once your troops have fortified an enemy tile for 1 (or more) full turn(s) then you gain the effect of the movement upgrade of that tile (maybe Railroad should be nerfed for this though maybe to 1/5 movement cost). Also, a unit must remained fortified on that tile in order for you to keep the effect, otherwise you will have to "reclaim" it. I feel it makes it more realistic.
Once you have control of an area for a while you can move through it freely, with only minimal fear of sabotage and ambush. Yes, enemies can bombard bridges and roads and take it away from you in real life... but that's already in the game.