Depends on which park we go to first, and if it is Extra Magic Hour Morning, or not.
At MK, if it is Extra Magic Hour, we go on Dumbo 1st, if not, we we go on Splash Mountain.
At Epcot, we always go on Test Track 1st.
At MGM, we usually go on RnR 1st regardless.
At AK, we go on Dinosaur 1st. We haven't been to Extra Magic Hour there since it has opened, but I would think we would likely go on Kilomanjaro Safari 1st.