We just did this yesterday and it worked great! Ecept, there is a quicker way, you can take the Downtown Disney bus and catch route 50 on the lynx at the corner of the intersection of E. Buena Vista and Hotel Plaza Blvd. From the DTD stop, walk behind the shops, earl of sandwich to the intersection. The stop to sea world is by the " hilton and the bank" side of the street.
The bus has a machine that take money right near the driver , 2.00 for most 1.00 for kids and seniors. The bus also stops a the "super station" near Circ du Solei, but I am not sure how to to tell which stop it is. The bus and the stop both say what route.
Hope this helps