What we do on arrival day depends, understandably so, on what time we arrive. We have AP's so we can pop into a park for a couple of hours if we so desire. But, if we arrive in the afternoon, we usually don't go to the park.
What we do on arrival day also depends on where we're staying. If we're staying in the Epcot Resort area, we often play a round at Fantasia Minature Golf, stroll the boardwalk, or take a swim. We usually have an early dinner and try to get to bed early so that we can hit the ground running on our first full day.
If we're staying at the Polynesian, we simply hang out at the resort and take in all the magic the Poly has to offer. The volcano pool, we stroll around, hang out on the beach, sip on a lapu lapu.
If I were at AKL in a savannah room, I could probably sit on the balcony and watch the animals for a couple of hours! They have a nice pool there from what I can tell, and I love the main shop.
PamNC