Hi Val:
I don't know that i would reduce the number of staging sidings. There's a neat opportunity there for some automatic operation when you're operating the layout.
There are ways to automatically switch turnouts using sensors. You could actually stage three or four trains.When one goes around, it would be set to go onto siding one. When it enters the siding a sensor would flip the turnouts so a train on siding two would then leave and go around your loop. When it returns to it's siding sensors would cause the turnouts to throw and allow the consist on siding three to go around. If you add a couple timers, you can delay the departure of the trains so they are not on top of one another.
In this way it will seem that there are several regularly scheduled trains each day. Meanwhile you can be happily working the yard over at the dock. Your guests will be wondering, "How's she do that?"
Regards,
Ted