Why are you leaving on Saturday? Unless you have plans on Friday night, get out of town after work and start driving. Assuming you get out of work at 5:00, you could theoretically be 7 hours away by midnight. Give yourself a jump-start and break up the drive.
I agree with Werner that going to Kings Dominion makes little sense on this trip but if you insist, I guess this is the best plan I can come up with.Friday night:
Leave and start driving. Get a hotel along the way, don't pre-book. Just see how far you get and when you want to stop look for an exit with a "lodging" sign. Maybe you can plan out a few options in advance depending on traffic and how far you get. We do this all the time and I highly recommend it.Saturday:
Keep driving, go to Six Flags America. If you get there late afternoon that's fine because it sucks and there won't be lines.Sunday:
Hersheypark - You're looking at a sh*tty drive here, but with a plan like this that's bound to happen. This is a flat out miserable stretch of highway, and whatever your GPS tells you should be taken with a grain of salt. You don't really need to stay at at Kings Dominion until close. Personally I'd leave around 7:00 or 8:00 and either drive to Hershey or within about an hour of Hershey. If you leave at 8:00 and drive until about 10 or 11 PM you can easily get to a point where you're close enough to Hershey that you don't have to leave until about 9am and you'll still make it by park opening. Just make sure you get past the DC Beltway on Monday night.Tuesday:
Knoebels - This is a FULL DAY PARK. Seriously.Wednesdsday:
Six Flags Great AdventureThursday:
Quassy and Lake Compounce - while there's no pressure to get to Quassy and Lake Compounce that early, when you leave Great Adventure it might be a good idea to start heading in the right direction for a little bit. Don't go over the George Washington Bridge. Follow the signs for FORT LEE as you head towards the George Washington Bridge (which you're not going over). Get off the Fort Lee exit and take the Palisades to 287 over the Tappan Zee, / Mario Cuomo bridge to the Saw Mill Parkway north. If you can get over the bridge and get a hotel in Tarrytown after Great Adventure (a 1 hour and 40 minute drive), you'd be doing yourself a lot of favors but if that's not possible that's okay too). If you pass Tarrytown and feel ambitious, you won't see another hotel for like an hour. Fair warning...Friday:
Six Flags New EnglandSaturday:
Drive to Kennywood but stop at Dorney on the way. Ride all the coasters, Demon Drop and the Log Flume and bail. It should take like 2 hours. No, I don't care if it's a Saturday. There won't be anyone there. This is pretty much a driving day.
Kennywood. Get there at open and knock out the coasters and major rides early, then you have a few hours for smaller rides and re-rides. Leave mid afternoon and drive home. That's a crazy day but the best solution if you want to include Kennywood. We frequently go to Cedar Point, leave at 4pm and drive 8 hours home. You're younger than us, if we can do it so can you. Luckily the day before won't be that stressful and you'll probably get in early so you'll be well rested.
I know that's a crazy last day, but the trip is inherently crazy. There's no way to completely avoid craziness but that should be the only crazy day as long as you leave Kings Dominion before park close on Sunday and start driving. You'll easily get on everything at Kings Dominion with time for re-rides by mid afternoon though so that isn't that crazy of a suggestion.
Personally I would skip Kennywood. It's close enough to you that you can probably hit it any weekend you want (drive there Friday night, go to the park on Saturday and drive home Sunday) and the rumors make it seem like 2019 is the year to go anyway.
Then you have a less insane drive home.