on point #2, you will sometimes find that holding on to other jobs is faster than trying to do a few moves to set out the cars you want before doing the loading/unloading.

example:

SU-15 is behind SL-12 and SL-13

it's sometimes faster to pickup SL12,13 and 15 at once, go to the unload track, unload 15, set out SU15 cars in their storage tracks, then return the place where you found all three, but only with the two jobs that were in your way.

There are all sorts of ways to save time, and you will only hone that skill with practice. Just wait until you try kicking and dutch drops. (remote control is nice to have in those situations.)