Imo, the only good place at Busch to eat is at the Smokehouse (I've been known to drive up for dinner there and catch an evening show).
In the past, I would assume it is true this year also, the only people who didn't have to pay for parking were season pass members. I don't know for sure, you may want to call and check. It does list the fun card on the page with the seasons passes now (it hasn't in the past). This may be a new thing this year (the park changed hands in 2009). Every time I've had to pay for parking in the past because my pass was expired, I was able to receive a refund by visiting guest services after purchasing the new pass.
If you do have to pay for parking, don't pay for preferred. There is a tram that runs regularly (you'll wait less than 5 mins for it to come around; usually it's only 2-3) for it to pick you up.
As a previous poster mentioned, there are picnic tables throughout the parking lot (usually they are pretty shaded), so if you want to pack a lunch it is doable. Whatever you do, don't eat in
Das Festhaus. Everyone who doesn't know better picks that place to eat because it's the only restaurant inside in the AC. The food reflects it.
If your family eats fast food, usually Hardee's has Busch coupons on their bags. Sometimes Wendy's does too. They are usually $10-15 off tickets. I haven't picked up any food from them lately, so I am not sure if they're running any deals right now. I do know that many of the local Food Lions and Bottom Dollars have $15 off coupons too (I saw them at Food Lion just this weekend); usually you just have to ask the customer service desk.
They have a fastpass system, BUT you have to pay for it. If I remember correctly it's pricey (I want to say it was like $20 a head). When they came out with it I was like, "I can do that at Disney for free." You purchase the pass at customer service when you enter the park, and they give you a little badge to show the line attendants at the rides. It's up to you if it will work for you or not. Busch is easily toured in one day without it because there are going to be things you'll look at on the map and know your family won't want to do. My suggestion would be to hit the coasters early in the day (if that's what your family likes) and then loop back to do the other things.
The theater in Ireland where they do the Irish ethnic dance show is very cramped. If anyone in your family is claustrophobic, he or she will not like it.
You may want to look outside of Williamsburg for food/things to do too. I don't know your entire itinerary, so that may or may not be possible. The Busch Gardens area of Williamsburg is only an hour from the VA Beach oceanfront, and there is a ton of stuff to do from Williamsburg to the beach. Usually, you will find cheaper (and often times better) food outside the tourist trap area right around Busch and colonial Williamsburg/Jamestown.
I haven't been to Jamestown in years. The last time I went was right after they discovered the old fort and the archaeologists were there excavating. I keep saying I'll go back in the fall (it's beautiful then), but I never seem to make it up there. It's a catch 22 on when to visit them, if you go on the weekend there are lots of tourists, and if you go during the week there are usually school groups. Pick your poison.
My number 1 suggestion (assuming you will have a vehicle while here) is stay off I64 near rush hour during the week. It will be gridlock city.
You may or may not have enough time for this to get mailed to you, but you should pick up:
http://www.vgnet.com/williamsburg/williamsburg_passport.php
http://www.vgnet.com/
The coupons in them are usually pretty good. Obviously, look at them with speculation, some are great deals and some aren't (as with any coupon book).
Feel free to PM me questions if you have specifics. The area is where I've lived all my life, so I probably have the answer to many of your questions.
