I made that drive a couple of years ago. We stopped in Destin, FL which has BEAUTIFUL beaches (white sand and emerald green water). We got up early the next morning and hung out on the beach for a couple of hours and then headed down to Orlando. From what I remember, it was still light out when we got there. On the way back we stopped in Biloxi, MS, got a cheap hotel and gambled for the night.
I live in Austin now, and the extra 3 hours each way was enough to push me to buy plane tix for our trip in Sept.
Chris