Unless there's a big problem with the new ride that causes everything to get really backed up for the hotel guests, I'd say your chances are very good if you get there at rope drop. I was at Islands earlier today and what the team members have been saying about the GP soft openings has drastically changed from last week. They're now telling people who arrived later in the day who are curious about WWoHP to come back tomorrow morning and they'll definitely be able to get in, as opposed to last week when they denied it ever happening.