I'm the minority. If the parks close early, spend your down time at the parks. Your kids are old enough that they should be ok. It takes a lot of time to go back and forth plus take time out for a swim. IF you are comfortable sacrificing 3-4 hours minimum of your park time at the resort, then go back.
We prefer to go all day, come back early if we don't want to see fireworks or whatever, spend some time at the pool in the evening. Nice way to wind down.
You could always play it by ear. We find that forward momentum keeps us going, if we stopped, it would be hard to go back! LOL
Have a great time!