I would most likely not set a time to leave Sea World and check into the resort. I would enjoy Sea World as late into the day as you want (it's an expensive one day thing), head to you resort, check in, grab a CS dinner there, and crash for the night. A full day in any park wears me out and I would want to be rested for the first of WDW the next AM. If you arrive early and want to do something, check to see where you can get an ADR for a place close to your resort, take a swim, a mono-rail ride, check out FW, tour a few resorts or if you have a ton of energy and want a late night,, hit DTD.