Oh, this schedule sounds like a fun challenge to figure out! Let me take a stab at it!
11:30--Arrive at the parks.
~11:35--Head to Cat in the Hat. After that, head over to the Poseidon's Fury show (this is a walking tour show that really eats up some time, you might want to think about skipping this since you are really press for time with the amount of stuff you want to do. The rest of this schedule assume you skip it).
~12:00--Depending on lines, you should be done with Cat in the Hat. Quickly look around the shops near Poseidon's Fury and head up to the bridge that lets you skip the HP area and takes you to Jurassic Park.
~12:30--Get in line for River Adventure. The line for this is normally short.
~12:45--Leave the Jurassic Park area and head to Toon Lagoon. Ride Dudley first.
~1:15--Depending on lines again, you should hopefully be off of Dudley. Head right over to Popeye.
~1:45--Again, depending on lines, you should be done with Popeye now. Start heading towards Spiderman.
~2:00--Ride Spiderman (I know this is not on your list, but it is WAY better than Poseidon's Fury and one of the best rides at Universal, you really should not skip it).
~2:45--Depending on lines once again, you should be done with Spiderman. Head over to the Hulk.
~3:45--Again, depending on lines you should be done with the Hulk (this gives you an hour for the line which should be more than enough). If you finish Hulk sooner, head to Dr. Doom. If not, visit some shops for a few minutes while you wait for the 4:00pm check in.
4:00--Check in at Hulk. If you did not have enough time after riding Hulk to do Dr. Doom, do it know. Do Single Rider if the line is longer than 30 minutes!!
~4:30--As soon as you finish Dr. Doom head over to HP and spend the rest of the night over here. 3 and a half hours should give you enough time to eat, ride the two major rides, and spend some time at the shops. If you get done early, you can also go and check out other rides that you liked during the day.
Now, this Schedule leaves off your lunch at Comic Strip. Since it does not sound like you are going to have the express passes, you really need to take advantage of all the time you have. To me, it seems pointless to zig-zag all over the park. By this I mean starting at the Hulk and then eating at Comic Strip only to have to come back to the Hulk later in the day. To get the most out of your time, you should only be visiting each area of the park once. Since you have to meet up at the Hulk at 4:00pm, you should do the stuff in this area just before 4:00 which would be too late for lunch. It comes down to what you want to do more, rides or food. I would take rides anyday. I would grab a quick snack when your hungry in either the Jurassic Park area or in Toon Lagoon.
Keep in mind the Toon Lagoon rides will make you SOAKED! Like, head to toe not one dry spot sort of soaked. Like you just jumped into the Ocean with your clothes on type of soaked. If you want to avoid walking around for the rest of the day with wet clothes, you might want to think about skipping both of these rides. The Jurassic park ride will get you a little wet, but not nearly as much as these two. If you end of skipping these wet rides, you will have enough time to fit in Poseidon's Fury. It all depends on if the group feels like being soaked for the rest of the evening.
When your planning, look at the park maps. Try to come up with a schedule of what you want to ride that limits the amount of running back and forth between areas of the park. You really should do the whole circle (skipping HP) and come back to HP after your check in at Hulk. I picked the path around the park that I did because it leaves you guy at the Hulk roughly around 4:00pm. If you start at the Hulk in the morning, you will have to backtrack to the same area wasting some valuable time to check in. Also, during the afternoon the HP area can be insane. Early morning (before you arrive) and the evening are the best times to visit which is why I suggested doing it after your check in.
One final note, don't share your schedule with the other groups! They will most likely either A) head for HP first or B) head for Hulk first. You guys will be most likely alone by heading to the Cat in the Hat first because the other groups will want to do the big name rides. Depending on the size of your whole group coming to IoA, the lines from all these different groups going to the same ride first might get really, really long.
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