I mis-spoke a bit about the engine needing to be running - the way you set it up and the way the window and headlight switch illumination works, they come on when the key is in ACC or RUN, not with key off or with the headlights switch.
Even then - even at night on my car the switch is easy to access and remember where it is and it only does one thing.
For cruise, you have 4 functions (Resume, Set, Accel, Coast) on three switches, so it gets hard to remember which does what. (Although I figured out that coast does the same thing as Resume if the system is on and disengaged).
I doubt I'd want to bother with modifying the Cruise buttons myself, but I'd be interested in reading what you come up with - or if someone else were selling lighted buttons.