Here is the answer I got from Gina when I asked a while back.
The information you are seeking is found here:
http://seaworldparks.com/seaworld-or...s?from=Top_Nav
Specifically (copied and pasted from the link):
What is the SeaWorld Rescue Tour?
The SeaWorld Rescue Tour is a look behind the scenes (~20 minute tour) at SeaWorld's rescue and rehabilitation facilities. Visitors will see areas established to care for sea turtles, manatees and other animals in need of help and learn about SeaWorlds efforts in fulfilling this mission.
How do I reserve my SeaWorld Rescue Tour?
Guests can book their tour only at the Expedia Local Expert Guest Service Desks at at our Official Hotels. The tour is only available to guests of these hotels, and is subject to availability.
When is the SeaWorld Rescue Tour available?
The tour is available every Saturday morning year‐round, and on all Early Entry Dates. Reservations and park admission are required. Please see the Expedia Local Expert Guest Service Desk for times and availability.
Park Discounts available to Guests of all Partner hotels...
What dates will the park open early?
Early Entry to SeaWorld and Aquatica, SeaWorld's WaterparkTM is available on select dates around the Easter Holiday, Summer Season (Memorial Day thru Labor Day), and during Christmas Holiday. 2013 Early Entry dates currently include the following:
o March 26, 30
o April 2, 6
o May 25
o June 1, 8, 11, 13, 15, 18, 20, 22, 25, 27, 29
o July 2, 4, 6, 9, 11, 13, 16, 18, 20, 23, 25, 27, 30
o August 1, 3, 6, 8, 10, 13, 15, 17 31
o December 24, 26, 28
Specific dates of Early Entry are subject to change. Please check with the Expedia Local Expert Guest Service desk in your Official SeaWorld Hotel for most current info. Guests must show benefits card to gain early entry.