Planning on one day park to park UO and IOA and 2 full days at EU. First time at EU and want to do the most I can! I'm hoping the masses will have gone home by the 3rd? Also, is it best to purchase them right away or wait until getting there? Will they sell out or will they be cheaper? (I remember a few years ago at UO they were trying to sell same day express pass for a cheap price as I walked through the park that day). I'm afraid to risk not having one but also would hate to pay $$$ if not necessary. Please advise.