OK, this is just my opinion so I’m not criticising anyone else’s view. I’ve not been to LA but have been to Orlando 5 times. Last time, my kids were 12 & 13. Firstly, the Holiday Inn Suites are an excellent choice. The location is perfect for all theme parks; especially if you want to have a mid afternoon nap with the little ones. Do get a WDW multi pass. I’m not sure what the current deal is but try to get a 6 day pass with 2 extra days in the water parks. Use them as follows.
MK - 2 days in week 1 & 2. The MK is great for all ages. One tip is to do the left side of the park first. Jungle boat, Pirates, Splash Mt, Thunder Mt & Haunted Manor. Book your fast passes for Space Mt, 7 dwarfs and Goofy coaster (or meet the Princesses if the little ones like that). The MK gets stupidly full after lunch so consider leaving for a rest at the hotel around 2pm and return around 5pm. Or do the sit down attractions like the hall of Presidents, Philharmagic or ride the MK railroad. Take a pram for the 3 year old and if possible, a buggy board for the 6 year old. Finally, the Be our guest restaurant is awesome but needs booking online 6 months in advance.
EPCOT - 2 days in week 1 & 2. EPCOT is very big. Pram is essential. Book your fast passes for Test Track, Frozen ever after and if possible Soarin. Lots of attractions for the whole family but more geared to older visitors. Again, consider a mid afternoon nap but come back for the fireworks around 8/9pm. Finally, try Germany for food. All you can eat BBQ.
DHS - 1 day in mid fortnight. DHS is a bit of a building site at the moment. Star Tours, ToT & Rocknrollercoaster are main draws. Little ones make like Frozen singalong and there and B & Beast shows and a Little mermaid theatre. You may finish DHS by around 3pm so have a rest and return for Fantasmic around 7pm. It’s possibly the best WDW show ever.
AK - 1 day mid fortnight. Fast passes for Exp Everest, Avatar and Na’vi River. Since Avatar opened, AK is now a full day. Lots of attractions but tends to close around 6pm. So think hard about a mid afternoon nap.
BB & TL. 1 day each bit remember 1 park will be closed during Orlando winter. TL has the edge for teenagers but I’d pick BB for 3 & 6 year olds. Both are really good and Mum can relax on a sun lounger all day.
Sea World. 1day. SeaWorld is great for the whole family. Sitting in the splash zone of the Orca show is a great experience but remember it’ll be cooler. The 3 Rollercoasters are arguably the best white knuckle rides in Orlando. Again. Lots of sitting attractions so don’t bother with a mid afternoon nap. Finally, arrive at the Shamu show 45 mins before the start. Dad & a teen can get snacks while the family save seats.
Universal - Now we didn’t do Universal last time. Mainly because my kids aren’t into Harry Potter and my wife wouldn’t ride anything in IOA. That’s not saying don’t do U.S but we skipped it to make room for other stuff like shopping and KSC.
KSC - Seeing the space shuttle was great but as for KSC, the boys loved it, the girls hated it.
Volcoano Bay - is very new and I’ve not been. Looking at their website, it looks awesome and possibly better than BB & TL. Remember it’ll be winter and hold off on tickets until you know how warm it’ll be.
Legoland - is targeted at young families ages 3-9. We didn’t bother as we’ve done the park in England.
Finally, the Vineland mall near your hotel is the best one. Also, consider booking a table at T-Rex in Disney Springs. Awesome special effects but average food. And if you like LEGO, the LEGO store in Disney Springs is approx half the price of Australia.
Just take a half empty suitcase. Happy Travels!