Hi KeithS,
We also have zero DC power "cigarette lighter" outlets on our 2015 303.
I was thinking of installing a couple, but am trying to wean myself off these archaic connections.
Since we almost always camp with shore power, we haven't really missed not having these.
If I were to install these, it would be relatively easy to come off the main panel to one under the hutch cabinets beside the light switches, or off the power to the audio system to the cabinet on either side. Remember that you are going to have to fuse these at less than the original circuit that you take the feed from.
Rob