MK:
Jungle Cruise
Tiki Room
Country Bear Jamboree
Small World
Peter Pan
Dumbo
Mickey's Philharmonic
Toontown
Buzz Lightyear
Tomorrowland Indy Raceway
Railroad
the parades
the fireworks if they don't mind loud noices
Maybes:
Pirates (just be aware that at the begining there is a very dark part, but nothing jumps out at you - if you can get them through that part they should love it)
Snow White - this really frightened my kids at this age - the witch does jump out in dark places
The 5 year old only: Splash Mtn, Barnstormer. My daughter who isn't a daredevil loved Splash Mtn at 5. The whole ride is tame and fun until the drop at the end. We just held her tight and covered her eyes and she never knew the difference!
I would avoid Alien Encounter at all costs!
Hall of Presidents is a good, long show and they may nap during it while you cool off!
EPCOT:
Spaceship Earth - it is dark, but nothing startling (see my tip for dark rides at the end of this post)
Univ of Energy - especially if they love dinosaurs (3 year may nap)
Wonders of LIfe - they can run around and the colors in there are bright. Probably wouldn't try Body Wars; but I bet they would enjoy the cartoons showing in there; The Making of Me is about how babies are made - this will lead to A LOT of question from the 5 year old
Living Seas - if they like looking at fish
The Land - Food Rocks and Simba movie (about the environment, but they will like seeing Simba); the boat ride is very interesting to adults and some kids - another one where the 3 year old may nap and I bet the 5 year old would like it
Jouney into your Imagination
Mexico ride
Norway ride
Illuminations (fireworks, loud noises)
Skip: Honey I shrunk the audience - it is fairly intense; the movies in China, Canada & France are great but probably won't interest your kids much
MGM:
The Little Mermaid show
Fantasmics!
Honey I shrunk the kids adventure zone - but be aware that it involves a lot of climbing and stuff for parents to keep up with kids
Maybes: Indiana Jones - 5yo should enjoy it (a stunt show)
Muppet 3-D show - a very funny show, but some kids don't like the way things appear to be 'jumping out at them'. Just have them take off the glasses if it bothers them. I was suprised that my kids did not like this at all when they were younger - they love it now. This is the tamest 3-D at Disney, judge from this one if Honey in EPCOT and Bug in AK would be something they would like.
Backlot tour: the tour part is pretty boring, but Catastrophe Canyon is fun and it isn't scary - maybe warn them about the water and fire is coming but you promise it will not get to them
Great Movie Ride - this is a great ride and they should enjoy it, but the Alien from the movie is kind of frightening to young kids. We just covered the eyes of our young kids during this brief section.
shows - many great shows, you know if your kids would like that
skip: Tower of Terror, Rock n Roll Coaster, Star Tours
AK:
Safari
Lion King Show
Boneyard (another play area)
Pocohontos animal show
jungle treks - seeing the animals
Maybes: -the shows; Primevel Whirl - the 5 year old would probably enjoy it - watch it and then decide
Skips: Tough to be a bug (the most intense 4-D at WDW); Dinosaur, Kali River
WDW in general:
definately do a character meal - I suggest on the last day of your trip. Then the kids have seen characters everywhere, they've gotten used to them. It is a good way to end a trip.
Hoop Dee Doo Revue - kids love this one
Characters - try to prepare your kids for the characters - they are large and many kids are afraid of them. Do they like Santa? that may give you a clue
Tip for dark rides: My kids were 'tense' on dark rides. They kept thinking something was going to frighten them (this was after the Snow White ride). So I got them each a small flashlight on a string to wear around their necks. We were clear on the rules: they could never shine them at anyone, they could only shine them in their laps or at their feet. This gave them all sorts of confindence! After a couple of days they didn't even need it anymore! You might try that with the 5 year old.
My #1 Tip (that you didn't ask for): don't push them. Rest everyday during the mid-day.
You will have a great time!