First off, congratulations! You'll love your stay at the GCH.
Theme park views will look over DCA and/or the pool. During recent stays I have requested a Grizzly Peak view; this is my particular favorite view. I like sitting on my balcony during an afternoon break watching the guests stroll by, and watching the rafts on GRR. Some of these rooms are very close to the walkways between Soaring and GRR. ToT is off in the background. Some people prefer the views looking out towards Paradise Pier. This is probably a prettier view at night with all the lights, but not as close to the action. By the way, I have twice called 3 days before check-in to request a Grizzly Peak view, preferably 3rd floor or higher, and both times I have been assigned a great room.