Thanks!

We are going there Thurs night through Sun eve on Labor day weekend.
I love that waterpark! Their cabanas are great deal for party of four - all of them come with towels (yours to keep) and included soft drinks as well as locker. We normally get the one next to hubba hubba and they have separate entrance to the lazy river. This time we are getting the one next to wave pool and it comes with food option included (buffet).
Busch Gardens is very nice, clean, well laid out and very well landscaped park. It is HUGE though.
If you/your kids are not into parks I would skip Bush Gardens (we are this time).
With your schedule I would downtown Williamsburg when you arrive on Sat. Please bear in mind that traffic could be horrendous (Sat-Sat beach rentals). Depending on how much time you have or how much interest your kids will express in it you can do just free walk around/look or get full access.
Sunday I would do waterpark and go downtown for dinner/shopping.
Sunday you can head to Jamestown (about 30 min away). A lot to see there, I actually liked it more than full access Williamsburg.

I would spend the whole day at the water park on Sunday. Get a wrist band thing, so you can cut the line.

Check out Colonial Williamsburg website to price out ticket options. A multi-day or flex pass might be your best option.

Go to Colonial Williamsburg on Saturday afternoon/evening and again on Monday b/f you leave. Check their daily schedule for tours and re-enactments: https://www.colonialwilliamsburg.com/plan/calendar/#EventSearchResults

I'd save Jamestown for when you have more time.

Love both Colonial Williamsburg and the water park. It will be a very fun vacation for your family.

The water park is nice and you could spend a whole day there, or half a day there and half at Colonial Williamsburg or Busch Gardens. Jamestown is a tiny bit of a drive, so you could do a half day there and whichever is closest. None of them are required, but if you do Colonial Williamsburg, you can also toss in a College of William & Mary tour, which has some nice features. Some people can easily spend a whole day at Busch Gardens. There's also a lot of shopping.

We are going down Saurday morning, coming back Monday night. 2 kids (8 and 10).

How should we spend our time there? Kids are excited about the water park - should we spend the whole of Sunday there? And is half a day enough for colonial Williamsburg? What about Jamestown vs Busch Gardens - can we get away without doing Busch Gardens?