Is there any shuttle or anything you can take between Disney and Sea World? We got free passes for Sea World and I don't really want to rent a car for one day just to go there. I'd rather not take a cab either. Thanks!
Some of the hotels near Downtown Disney (still on Disney property, so you could take a bus to DD) have shuttles to Sea World and USF & IOA. There is usually a charge though, I think it was $30 RT for us per person.
Your best bet would be to rent a car or take a taxi. It will probally be the cheapest when it comes to price and the time that it will take to get there.
If Lynx is still running from TTC, you could take a bus but have to transfer to another one I think. I'm not sure if that's still available or not. I never did it and didn't need to. Someone in Orlando might be able to help you out.