In MK, I would start with Barnstormer and then work your way up to 7DMT, BTMRR, Splash and Space Mountain (I would suggest in that order, but if your kids are hesitant about drops, you may want to switch Space and Splash around). My DS9 has yet to do Haunted Mansion and has no interest. He was afraid to go to sleep after seeing Fantasmic a few years ago and I don't really want to repeat that experience on vacation with HM!
In AK, we have yet to do It's Tough to Be a Bug and it's unlikely we will do it. I can't comment on FOP because we haven't ridden it yet, but I would probably save FOP and Dinosaur for last. DS didn't ride Dinosaur until he was 8. It was actually hysterical as there was a younger girl in our car who screamed the entire time and then when she got off, she begged to go again.
In EP, I think it really depends on your kids. If they are afraid of heights, do Soarin' last, speed TT last, drops FEA last (though the drops are very tame, you could just warn them that as soon as Elsa sings "Let it go!", they will drop backward and then one small drop at the end)