For questing you need a keybind for Interact With Target and the Jamba addon. My quest accept/finish is like this...

1. on main select the questgiver
2. press the 'target main's target' button (macro on slaves)
3. press interact with target
4. on my main accept quest/etc and all my slaves do what my main does, jamba takes care of everything on the slaves

You could combine some steps but i like having a 'set target' for my slaves and interact on separate buttons (i use the first in combat and for other things).

I follow the same steps for flying... target on main, interact on slaves and just select a destination on main. The slaves select the destination automatically.

Hope it helps.