vacation suggestions?

So I am planning an actual vacation in August with one of my very bestest friends. And her 4 year old son.

Our original plan was to take Skybus somewhere for cheap. That's not happening now, so we're looking at alternative options.

Preferably spots we can drive to within 8 or 9 hours, or even less. (Remember - there will be a 4 year old in the car). We're leaving from C-bus. We'd like a beach. I'd like more of a city than country.

And I'm ready for your suggestions...