Kings Dominion is celebrating their 40th Anniversary this year so the park has done a lot in terms of landscaping and painting. Weekends tend to be pretty crowded and they do run buses up from Richmond on weekends in the summer, so the water park can be overrun. There are some good coasters there, Intimidator 305 and Volcano two of the best. There are also two classic wooden coasters there, Rebel Yell and the Grizzly. Count on long lines for most of the rides especially on weekends. The food there is overpriced, but they do have a Chick Fila, Starbucks and Rita's there.
https://www.kingsdominion.com/
Busch Gardens is by far the one of the nicest parks within 3 hours of DC. The grounds are landscaped beautifully. The food is very good to excellent, prices are high, but not as overpriced as KD. The park only has 5 roller coasters (compared to 14 at KD) so the waits tend to be over an hour on Saturdays. VA residents can get a funcard for the same price as single admission which allows you to return to the park for free until Labor Day.
http://seaworldparks.com/en/buschgardens-williamsburg/
Six Flags America. This park has cleaned itself up a lot over the past couple of years. Superman and Wild One are the best coasters at the park. Recent coasters additions are transplants from other Six Flags parks. Food is forgettable and overpriced. Waterpark is decent, but can be over run by city kids bused in from DC on weekends and DC school groups during the week in late May/early June.
https://www.sixflags.com/america
Six Flags Great Adventure (NJ) - one of the best parks on the East Coast if you like roller coasters. Kingda KA has a 456ft drop. El Toro is one of the best hybrid (wood and steel coasters) in the country. Decent food, priced kind of high because of its proximity to NY. Offers a Safari ride in covered 4X4s with up close animal experiences for an additional fee. Because of its proximity to NY and Philadelphia, can be very crowded on weekends.
https://www.sixflags.com/greatadventure
Hershey Park - great coasters, great atmosphere, and chocolate! Good food, nice selection of eateries including a sit down restaurant. Nice waterpark included in admission. Simulated factory tour and and huge Hershey store where you can load the kids up with chocolate for the ride home. Also offers a zoo for an additional fee and 4-D movie at Chocolate World. Can be very crowded on the weekends. Rooms at the affiliated Hotel Hershey (which offers a free shuttle to the park) run $350 - $700 a night on weekends from April through October.
http://www.hersheypark.com/
Knoebels Amusement Park - (if you are heading to Hershey and want to make a weekend of it!) Excellent family owned park near Williamsport, PA about 90 minutes north of Hershey. No parking charge, outside food welcome. Excellent food on site. No admission charge! Pay by the ride by purchasing tickets. Excellent wooden roller coasters. Classic antique carousel where you can still try and get the brass ring!
http://www.knoebels.com/