You may want to think about spending ONE night at one of the hotels at the parks. Becuase this is around Halloween, Universal goes ALL out for Halloween Horror Nights. Becuase of this, park hours at the studios will be really short most nights to prepare for the event that night. Normally the Studios closes around 5 and IOA closes around 6 maybe 7. However, in years past, both parks took part in the
HHN events and so both parks might close early.
So, staying at one of the hotels for ONE night will give you express ride access with your roomkey for TWO days. Simply show your room key at most rides/shows and you are riding the ride in about 10 minutes. The express does not work on the new harry potter ride or the Rip Ride Rockit (which I doubt you will do).
Since the parks will be closing early, I do not think you could do all the of rides and shows at both parks in one day. I am going to break down each ride that I think you could handle.
US:
Shrek: A very family friendly "show". Its a 4D adventure into the world of shrek. The show lasts about 7 minutes and the only thing thats different about it, is the seats you sit in move around a little bit. So, when shrek is riding on a horse on the movie, your seats will rock back and forth like your on the horse as well. The seats do not move very much, so I would not miss this show!
Twister: Its a standing special effects show that lasts for a few minutes once you get into the main room. The first two rooms explain how the movie was made and the work that went into it. The last room is a special effects soundstage where you stand and face a scene from the movie that has a twister come. Its a really cool special effects show that puts you into the movies.
Diaster: This is another special effects type of "show". You get to experience an earthquake while sitting in a subway car. The cars move up and down with the action that is taking place around you. It has fire and loud noises, but is another one that I think you could handle becuase it is not fast or anything like that.
Jaws: Jaws is a fun ride but my sister is still scared to ride it! She is afaird she is going to fall into the water, lol. If you can handle jaws, you can easily do Diaster and Twister.
MIB: You will LOVE this ride! Its like Buzz, but SOOOO much better! Since we always stay on site and get front of the ride access, we will ride this ride 5 or 6 times in a row in the course of maybe 45 minutes. You will want to do this one again and again!
ET: A very family friendly journey with ET. You will really like this one as well.
T2: A very cool 3D movie that also has live action on the stage. It is the only 3D show I have ever seen that has live actors on a stage that interact with the movie. Its a really cool show.
Simpsons: If you can ride things like Star Tours at Disney, you should be able to do this. It is a little more jerky than Star Tours, but if your family likes the Simpsons, you will enjoy it.
Shows: I would see the Animal Actors Live on Stage show and maybe the bettlejuice show. I am not a fan of the bettlejuice one, but it can be fun if you have time.
Do Not Ride: Do not ride Mummy or Rip Ride Rockit. Both of these are roller coasters. The Mummy is a really, really fun rollercoaster that is very mild (only goes about 30-35 MPH). However, it sounds like it might be to intense.
Islands of Adventure
Spiderman: If you can do Simpsons, you should be able to do Spiderman. It basically takes the car you normally sit on for rides like Simpsons and Star Tours and places it on a FLAT track that moves around the building. You will move from movie screen to movie screen. It can be scary for little kids becuase of the villians, but it is really cool experince.
Storm Force: This ride is just like the tea cups at Disney. If you can ride those, you can do these.
Popeye: If you family doesn't mind getting wet, Popeye is a really fun boat ride. Towards the end you will go up a big hill, but don't worry! The ride does not have a drop in it that is major. You normally only go down 2 or 3 feet at max. The hill is at the end of the ride to get you back up. Its a great ride for the whole family, but be ready to get wet!
Jurassic Park: I really had to debate if I should put this here. It does feature a big hill at the end, however the ride itself is really fun. You can watch the people coming out of the building after the big hill and judge for yourself. The building is really tall, but you do not go to the top of the building. I would guess that you are AT LEAST 3 stories below the max in the building.
Harry Potter FJ: This is the new ride. If you can handle Spiderman or even the Simpsons, I think you should be fine on this ride. It is a slightly more intense version of soaring. I would suggest giving it a try. If you don't like you, at least you can say you got to ride a ride with Harry Potter!
Posiden: This is a cool special effects show. You are guided through different rooms until you arrive in the final showdown. Lots of fire and water create a really neat show.
All 4 rides in Suess: This is a really cool area of the park! You will be able to ride all four rides in this area and will like to explore the shops and stuff. One of the rides even has two different tracks that provide two different rides.
Shows: See the Sinbad show! Its a really cool show that I think your family will really enjoy!
Do Not Ride: Hulk, Dr. Doom, Dragon Challenge, or Dudley Do Right. Hulk and Dragon Challenge are big roller coasters. Dr. Doom is like Tower of Terror except you shot up instead of being droped down. Dudley Do Right is a boat ride that features 2 or 3 hills with the last one being really big. You MAY want to ride it since you can see a lot of the ride from the outside. You will have to be the judge there.
Sorry about the length of this post! I just wanted to break everything down for you. As you can see, there are a lot of things you might want to do. If want to do it, I really suggest the one night of hotel. Depending on how much time you want to spend at Harry Potter, you might not have enough time for everything else. Two days will be just enough time to not feel rushed.
However, if you can only do one day, make sure to plan really well! The halloween stuff really can mess up plans. I DO NOT suggest going to the Halloween event! It is EXTREMELY intense event that is NOT suggested for people under the age of 18. Keep in mind that a lot of the props will be out all day, but none of the actors will come out until the park has been closed to prepare for the event that night. Enjoy your trip!!!