Most likely DCA will close at 10:00 and DL will stay open until midnight. I would get hoppers. Carsland is beautiful at night. Sometime around dusk or dark, I would do a single rider line at RSR and enjoy how pretty Carsland is, and I would hop to DL to get that last 2 hours of park time. With just adults you can move faster than when you have kids along, and a DL you can be out of one park and in the other in 5 minutes, so I would get hoppers and hit the highlights of both. The nighttime entertainment can take quite a bit of time investment, so I don't know whether you want to take the time with it, as limited a visit as you are going to have. The new Paint the Night Parade is running a 2nd time at 11:00, so you might be able to catch that second showing without a horrible amount of wait time as the crowd should have thinned out some, if that is something that interests you.