One of the (many) great things about SeaWorld is you don't need the kind of pre-planning for your day there like you do for one of the Disney parks. Especially when you have Quick Queue passes (which are awesome), you can have a much more go-with-the-flow kind of day. Its truly a wonderful feeling!
I would hit Antarctica at park opening as that attraction has yet offer QQ access, and its very popular as its brand new. I know that might mess with the early morning dolphin feeding, but hopefully you could take part in one offered later in the day. Unless the dolphins are your priority, in which case make them the first stop like angelmom suggested.
I highly recommend the all-day dining as well, if you haven't already purchased it. Its an excellent value, truly unlimited (even beverages) and the food is excellent.