When using shore line power do I need to have the inverter on? Do I need to have the coach batteries turned on? Do I need to keep the Engine batteries on?
Inverter itself doesn't need to be on, but make sure that turning it off does not also disable the 12v converter & battery charging function. It doesn't in my 2004, but yours has a different system. Basically you can leave the inverter on all the time - there is seldom any reason to manually turn it off. It won't actually invert unless shore power is lost.
Leave the battery switch on, so that the batteries continue to receive a charge while on shore power. Likewise for the engine batteries. Your coach has automatic systems to manage this and you don't need to do anything.
Is your coach equipped with the Heart Source Manager II? If it is, it contains circuitry that protects against miswired shore power outlets and over/under voltage.
2004 American Tradition; 2014 Buick LaCRosse
Homebase in the Ocala Nat'l Forest near Ocala, FL