Hello fellow chicken! I typically skip the big rides, too, and think that Dumbo The Flying Elephant is just the right speed and height for me :-)
Here is my list of rides I skip and those I brave:
Magic Kingdom attractions I avoid: Astro Orbiter
Magic Kingdom fast-ones that I try to do: Splash Mountain (does have one large drop, but otherwise is pretty smooth), Big Thunder Mountain, and Space Mountain (this is fast and in the dark, but no upside down; I usually work up the courage for 1 ride and then call it quits while my family rides it many other times)
Epcot attractions I avoid: Mission Space
Epcot fast-ones that I try to do: Test Track, Soarin
Disney's Hollywood Studios attractions I avoid: Rock n Roller Coaster, Tower of Tower, Star Tours
Animal Kingdom attractions I avoid: Expedition Everest (this is like Space Mountain for me; i do try to get on it at least once - it is very fast and dark, feeling like it does go upside down) and Primeval Whirl
Animal Kingdom fast attractions that I try: Kali River Rapids and Dinosaur (can be scary & bumpy)
All the rest that I didn't list are all ones I love! I hope this helps in your planning.