If you are utilizing EMH, you can't start at Thunder Mountain because only Tomorrowland and Fantasyland attractions are open for EMH. So, start in those 2 areas doing the rides that you want to do most. The other lands will open at 9am and you can head to do those.
So based on this, My plan would be something like this:
Check night before hours haven't been extended.
*Arrive 45minutes to 1 hr before park opens. This is for two reasons.
First, if they see there is a larger than normal crowd, they will open early, even in off season. It is not unusual for them to let you in 30 minutes early. Sometimes you are confined to Main St, but in is in. You can get maps, lockers, strollers, all that stuff before the park is even officially opened.
Second, being very first through the ropes really does make a difference. If you can stay on track and stay ahead of everyone else, even by only a few minutes it can save you a lot of time. If you walk straight onto the first ride and second rides, wait 5 minutes for the third, 10 for next and so on. It is a big advantage over someone who got there at or right after opening, but by the time they made it back to a ride the waits are already 10-20 minutes. If you were in the park first, you should be about ready for your 3rd or 4th ride by this rime, while they are only getting in line for their first.
1. Tomorrowland first (go into park down main street, make sharp right cutting through Tomorrowland Terrace if u can)
A. Space Mountain for daughter who likes coasters & Buzz or the Transit Authority for the other daughter - Transit Authority is fun but not that much fun, unless you just really want to do something different or it is a favorite. I'd just do Buzz. Most kids want to do Buzz over and over again. It's hard to tear them away.
B. Ride Buzz a second time with both girls.
C. Astro Orbiter if desired because it is such a small capacity ride that it will get long lines fast later on. If its not a big priority, skip it.
* I'd skip Stitch for two reasons, 1. There are better ways to spend your limited time on a busy morning, and 2. It has about a 50/50 chance of traumatizing your children.
*Laugh Floor is not open early, but save shows for later in the day anyway as you will wait no matter what for those.
*The Carousal of Progress won't be open yet either, so don't worry about it. This is another one that I'd put off until last anyway as people either love it or hate it. It's more a show tan anything and not as exciting as other options with only one day.
*I'd also skip the Speedway unless it is a must do for your girls. The cars move pretty slow on fixed tracks. I don't really understand the appeal unless you are a toddler who is too young for go carts, or just really into cars.
2. Fantasyland
*Skip Dumbo and Barnstormer. Save them for later because waiting for Dumbo is not as bad as waiting for other rides. It is actually a nice break because you get to go in a nice shaded indoor area while the kids get to play on a circus themed indoor playground.
A. Tea Cup - if it is a must do, the line is still short, and the line for PP is still short. Riding now will save some time. If there is a line, I'd just skip it and try later.
B. WTP & PP - if PP wait is still pretty short, do WTP first. This will save you some back tracking. If PP is already getting crowded which is very possible do it first, then back track to WTP or save for later. Both are extremely popular lower capacity rides, but WTP has the new interactive wait line. If you have to choose one to spend some time waiting in WTP is the better choice.
* Skip Little Mermaid, Mickeys Philharmagic, & Small World for now.
3. Liberty Square
* Skip HM, Hall of Presidents, and Riverboat. You can come back to HM. The other two are if we have time rides to me.
4. Frontierland
A. Big Thunder Mountain
B. Splash Mountain (if it was open, it won't be for your trip)
* Skip Tom Sawyer Island - it's not really anything to do just a park to play in
5. Adventure-land (if any of the below are big priorities for you) if they aren't skip to step 6, and catch Adventureland last before you leave the park
A. Jungle Cruise - if it is a must do only. If not, I'd skip it. It's fun, but not as much as other attractions IMHO, and you won't be able to fit everything in anyway. It's another low capacity slow ride, so lines can build, but its not extremely popular, so you might have luck hitting it later at night as well. I'd save it for a last if we have time ride kind of thing.
B. POC - if interested, not sure if your girls like Pirates or not, but this is pretty popular so ride earlier or later at night
C. Tinkerbelle Meet - if line is 30mins or under, if not the line remains long all day, so it doesn't matter when you come, save it for later
D. Aladdin - if its a must do, otherwise Dumbo is the same concept, so skip it
E. Enchanted Tiki- if its a must do and a show will be starting soon, otherwise save shows for later on
* Id also skip Swiss Family, its neat, but just a self guided walk through, you can do it anytime
6. Liberty Square
A. HM
7. Fantasyland
A. Small World - if a must do
B. Mickey Philharmagic - one of my favorite attractions, but since its a show, you should be able to fit in anytime really.
C. Little Mermaid (walk behind the Dwarf Mine Train)
D. Dumbo & Barnstormer (There is a water play area younger girl can play in while older rides coaster)
E. Tea Cups - if skipped earlier
8. Moving in a circle, go back a hit anything you skipped earlier like shows, playground areas, or rides that weren't your first priority the first time around.
This plan minimizes walking. You pretty much just make two to three loops around the park. The first hitting all the most popular attractions, the second and third going back and hitting the mid to least popular. How many loops you will need, and how much waiting you end up doing, will depend on how fast you can move from A to B, stay on plan, and how crowded it ends up being. On an off season day, I could easily make my way from Tomorrowland to Thunder Mountain in an hour, and complete most of the plan, at least through step 6 by lunch. During peak season, you may only make it through Tomorrowland. Especially if your group moves slowly or gets hung up re-riding things like Buzz, or distracted by gift shops, snacks, bathroom breaks, etc.
In my experience, if you stay on track, you can ride about the same amount of rides in the first 2 to 3 hours the park is open as you can all the rest of day. You can easily do 8-10 or so with a good touring plan. People just don't like getting up early on vacation. So until between 10-11, its usually not too bad. If it ends up being super crowded, though, and they open earlier than originally planned, all bets are off.
My advice, use this as a guide. Figure out your priorities, then plan to hit the most popular of your priorities first in one loop around. Then break / lunch and try for a second loop catching things you skipped the first time. Read up about which rides people in general dislike, have issues with, or say can be skipped. Then save those for a trip when you have more time. That will help you narrow down everything else into Must Do and Would Like To Do If There Is Time.
Hope I haven't overwhelmed you too much. And this is just my opinion. I know others would do it differently, but maybe it will help some.
