We went to Sea World from WDW but we used Mears, it was the cheapest and it was very easy, they came and picked us up at the main lobby area, and dropped us off at the gat of Sea World we made plans to have them pick us up on the return trip they came at about 5pm and took us back to the resort. I think it cost about 40.00 for two round trip.
Last year we did a rental acr and that worked out well too, the rental company will provide transportation to and from the resort. Day rate enede dup being about 68.00. They get you with all the insuracne nonsense.