Most of these require ridiculous paperwork and slow the game to a crawl. Leaving them out is less realistic but more fun. Armored men can not swim . Cross rivers only at bridges. Doors, drawbridges, etc.
Buildings provide complete cover.
Men shooting down from the top of a cliff have cover from men below. Retreat is a full move away from the enemy. Defender rolls-if hit, attacker rolls for survival. Defender rolls-if hit, attacker rolls for survival. If ladder men win, put on wall.