As much as it kills me to admit it, Universal's Islands of Adventure (where Harry Potter is) is an amazing park, right on par if not better than some of the Disney parks. If you are staying off sight, I wouldn't miss it. But, 5 park days in a row could really do you in! I think if it were me, I'd do MK, HS, a day off by the pool, then IOA, and EP. Using crowd calendars to pick which parks on which days. Save AK for your next trip because you will be back! Islands of Adventure has SO much for your girls- especially if you like Harry Potter, but even if not. Your DD4 will love the Dr. Suess section, and both will love the Jurassic Park play area. I love all the Disney parks, but I think there will be a lot more there for your boys than at AK, if you had to choose. Also, my DD10 just told me that she'd SOOOOO rather do IOA than AK any day and she's done both! Hope that helps!