While it probably isn't a longer walk from GV to Aquatica than it is from CH to Sea World, I think that the nature of the budy traffic along I Drive would make the walk quite unpleasant and I think that there's no sidewalk along that stretch. And then there's the traffic moving in and out of the little shopping center and the gas station near the intersection. I know that there's a traffic light at the CFP/I Drive intersection but, until you mentioned it, I didn't know that there was a crosswalk across CFP on the Grande Vista/Aquatica side of the street and I wonder if there's any reason for it other than to get from one side of CFP to the other.
I think that GV to Aquatica would be a much more difficult walk than the walk from CH to Sea World, where the traffic is much lighter and you can use the sidewalks for almost all of the trip.
Dick Taylor