My 10 year old daughter and I stopped in Williamsburg on the way home from Myrtle Beach for 2 days, we ended up extending it to 3 days just in Colonial Williamsburg alone, she loved it there- we went back 2 years later for 4 days there.
I have been to CW many times. Recently it seems to have gone down hill a lot less interaction and rein-actors roaming the streets and that was much of the allure. The Ghost Tour is okay there are a ton of them going on at the same time. I would not hesitate to go there or Yorktown or Jamestown if you have never been before you will not know the difference. I agree that the amusement parks are kind of a waste but if you get a chance visit the Yankee Candle, It would only take 30 minutes or so but they have a winter scene with real snow falling.
I would save i305 for the last coaster to ride. It is the only coaster I have ridden that caused me to gray out from the intensity and it gave me a headache that took over an hour to go away.