My 1969/70 Explorer Class A had both lighting circuits/systems. All of our use was off-grid so the 120VAC system was redundant and unnecessary.
Not sure what the 1972 Executive Class A has. (Haven't done much with it since it was given to me ... as project needing work before using.)
What I was trying to say is you can have comfortable interior lighting without putting excessive strain on your deep cycle battery or power converter. (Power converter is on shore power or a generator so lighting becomes functionally the same as a separate 120VAC light system.)
A single Thin-Lite LED112P, left on constantly for 48 hours, uses 38.4 amp/hours ... well within the capacity of most deep cycle batteries. I might do that for experimental test purposes but just about everyone else wouldn't.
(BTW - we used Coleman propane lanterns to supplement the 12VDC electric lights.)
