I thought about doing the same thing.
My plan is to run an inline fused wire from the positive battery cable at the starter to a switch mounted inside the engine compartment, then to two LED lights, one on each side of the engine compartment, and a RED indicator LED through a spot on the outside wall to indicate lights on.
I would avoid hooking it up to the panel light circuit only because I would keep the panel lights on when the generator is in use. No need to energize the inside lighting if not needed. By connecting at the positive battery terminal at the starter(WITH A FUSE IMMEDIATELY AT THE CONNECTION) there is no worries about the amount of current drawn by a couple of multi LED lights.