I discovered today that the key combo Ctrl-Alt-v will switch between focus of objects in the simulation.
say you have mars and it's moons. you can toggle the combo between. focus on diemos and mars, focus on phobos and mars, focus on phobos and diemos. (depending on what object you have selected)
and it will automatically keep the 2 bodies in view. orbiting the camera around in both horizontal and vertical without camera orbit turned on
it's pretty neat.
I had a look at the complete list of controls and this isn't listed.
(I only discovered it because tha'ts the combo I use to capture video)
edit:just Alt-v works