See First in Speed Run
An agile character is a good idea here, though not neccessary. This one really depends on your ability to dodge the horses and pick up treasures at the same time. Run up and down the area picking up treasure. Press
to zoom the map in, it can be easier to dodge horses when you're running with them to your back if you use the mini map. Defense Captains will drop keys that stop the horses for a few seconds. Generals will appear that drop large exp pouches if you can kill them before they run through.