The Roger Rabbit FP return bypasses the queue. The RSR FP return you will pass the structures in the middle but miss the signs on the wall in the switchbacks, though you can still kind of see them. Pretty much nothing else bypasses the queue when you return. For Soarin', Space, Star Tours, ToT, Splash and BTMRR you are seeing the entire queue. Apparently for Indy there are some items outside, but you see everything inside, which is like 95%. On Autopia I think you bypass some advertising. It's been probably 10 years since I've done standby there, but it's wasn't all that special. Goofy's Skyschool, GRR and Screamin are just basic outdoor queues. I think that covers all of the FP rides.
If you go single rider on Splash or Indy you will miss most of the queue. On RSR it's equivalent to the FP queue. On Matterhorn, GSS, GRR, Screamin and Soarin you're not missing anything, though Soarin doesn't save you much time.