If doing breakfast, you may want to consider Five Forks Cafe. It's off the beaten path and seems like a hole in the wall but the food is really good and I felt the service was solid. Honeybutter's is I think a sister restaurant, though I could be wrong. IIRC that was pretty good as well.
A lot of people also like the Old Chickahominy House. We liked it, but it was kind of cramped.
With all of the really good places for breakfast around, my suggestion is not to even bother hitting a chain for breakfast as most of them can't hold a candle to the local businesses. Though I do love me some Cracker Barrel pancakes for some reason.
Another place I'd like to tell you about is Sno-to-Go. We had been to Williamsburg maybe 7 or 8 times over 11 or 12 years before we realized this place two years ago. We must have driven right past it a hundred times.
They have really nicely priced and generously portioned soft-serve ice cream and sno cones. The people there are really friendly and very understanding and adept when it comes to food allergies (that's a concern for us).
Also, although it's a chain Bruster's ice cream was really good as well. The people there were even more friendly and helpful than Sno-to-Go (which is not to take anything away from Sno-to-Go).
There was a Mexican restaurant in the New Town area of Williamsburg (next to It's Sugar) that we've been to a couple of times. We liked them a bunch as well. Definitely seemed budget friendly, if I remember correctly. Coupons might have been available somewhere as well.
So, between what I posted here and what I've posted before (Pierce's, Food for Thought, the Cheese Shop) I've given you some of our must-dos. Hope you enjoy!
BTW, be sure to ask for some "ends and dressing" at the Cheese Shop. It makes a great alternative to chips and is something that we're usually able to keep as an all day snack for the family. I also love their chicken salad (bacon and almonds in it, IIRC).
If you're going to Busch Gardens, our favorite is
Das Festhaus. It has German food (yum!) but a bunch of other options as well, AC, and there's usually a show going on.