I'd arrange for a car service. It probably wo'nt be any more expensive than a cab, and you could have a definite drop off and pickup time. You could call Jim 407.869.9007, he has a gorgeous white stretch if you want to splurge, otherwise he could also set you up with a towncar.
I'd plan for more than 30 minutes. I'd give myself an hour, if you get there early there are TONS of things to see at DTD. Actually, if it were me, I'd probably plan to get there two hours before doors and have dinner beforehand at one of the wonderful restaurants.
Anne