It really depends on your kids and what you know might freak 'em out. Every child is different and what might scare an 8yr old boy might not even bother their 6yr old sister.
My 7yr old son for example, has no fear of any of the "thrill rides" that his mother refuses to get on, but does not like loud noises or dark/spooky themes. Indiana Jones and TOT are good examples, for he loves the rides themselves, but hates waiting in the themed queues as the mood they set stresses him out .
A child's perception of what's real vs. pretend also comes into play. When my son first visited DL and other theme parks a couple of years ago, we found that he took the stories/background/mood of certain attractions quite seriously and got very scared when he thought that he was in real danger (Prime example: "It's Tough to be a Bug" show).
You would be the best judge of what your kids might be stressed by but here's the top list of what my child had problems with when he was younger:
1: It's Tough To Be a Bug
2: Indiana Jones
3: Tower of Terror
4: Haunted Mansion (regular and NBC)
Now, he'll ride the last 3 items on the list (if the line is short enough)
.
) and California Screamin (If I had kept them from seeing how it starts, they may have tried it).
