Is there any benefits to going late one evening and then going back the next day?

Yes, they sometimes have discount tickets if you go in after a certain time. Other than that, no benefits other than it may be less crowded

If you have a Seasons pass you can go and come unlimited plus get 10% pff on food and pictures Also you get free parking which 20 dollars just to enter the park

Check the Carowinds website for tickets. Sometimes they will have a discount if you go late in the day