One properly sized fan at the vent of your choice will pull air into the basement/crawlspace and exhaust it outside.
This only works if the air you're pulling in is dryer than the air in the basement.
Based on the dimensions you provided, a 400 cfm fan would provide one air change every 22 minutes.
A fan controlled by a humidistat wouldn't need to run 24/7.
Why do you think you need additional ventilation? Is there moisture damage evident?
