We got back from our early May trip and I am still in shock over what their fav rides were! My ds1 (5 yrs) and ds2 (3 yrs) have their own favorites!
5 Yr old favs:
Buzz
Matterhorn
BTMRR
Space Mtn
Star Tours
Mulholland Madness
Splash Mountain!
3 yr old favs
Star Tours
Buzz (this one they agreed on)
Tiki Rm
Pooh
POTC (wanted more slides - ie drops!)
I was so surprised that my eldest turned out to be an adrenaline junky!

He's usually pretty cautious - who knew?
That said, you also got pretty good advice from the pp's
Another vote for stroller - bring a DOUBLE OR TWO STROLLERS! We had a baby carrier for our youngest (19 mo) which we would strap her into for the long walk to/from the park, and the boys would ride. It's just too long to expect them to walk and not be dog tired. Transportation for each child is a must - even dh admitted this after our trip (I twisted his arm in the worst way to be able to bring the double stroller.....)
Another vote for naps/rest in the pm's. We went back to the hotel every day for naps, and though my kids do still nap at home, I would think this would be beneficial even to kids who don't usually nap - they get pretty tired with all the action and stimulation, and we noticed that exhausted, pushed too hard kids aren't good touring partners!
Also recommend snacks - good to pass the time while and older sibling is on a ride which younger sibling can't ride (there aren't always nearby appropriate rides, and splitting up can add a lot of wasted "where were you - we couldn't find you" time....(speaking from experience....

)
Also a tip we tried to stick to - if you are doing lunch at the parks, and it is a sort of busy type of day crowd wise, try either an early or a late lunch - the restaraunts are really busy between 12 and 1:30, and lines are LONG! We usually had a light early bfast, snacks mid morning and lunch by 11 - the longest I waited in a counter service line was about 1 minute, and that was our first day at Red Rockets when I couldn't find the juice boxes so the CM went to get them for me himself!
Most of the time our 3 kids shared a kids meal - the portions are quite large, and the kids were always more concerned about getting back out at the park than eating a large and complete meal!
Most of all, be flexible - your kids will freak out/not care about rides you thought they would love, and they will love rides you never thought they would care about! We did FL once, and neither child ever cared to go back!

And I thought that would be their favorite place?!?!?!?!
Have a fabulous time! The ages of your kids will make this trip that much more magical for you! Seeing DL through the eyes of my children was the most amazing part of the trip for me!