Cavalry Charge bonus...

[plloyd1010]

You and Jen wanting to add restrictions seems to be the first complication. I don't see why such restrictions are need, as most of the terrain you listed already gives a favorable modifier to the defender. I only see a cavalry charge as getting the attacking cavalry in amongst the defenders quicker than usual. The old style charge of running down the peasants went out with the ACW, though some officers wouldn't figure that out for another 50 years.