Back to an original root cause of the dilemma:
No matter whether you plan your layout for DC, DCC or onboard radio control with steady state AC track power, it’s always a good idea to insert insulated rail joints anywhere that might be necessary for ‘Primative Pete’ DC (a’ la Westcott’s How To Wire Your Model Railroad.) You don’t have to run the feeders through switches, although it’s a good idea to gang-wire to your busses with some form of screw terminal strip or similar. That way, adding ‘kill’ toggle switches for some ‘stored out of service’ trackage, or separate control zones, or, especially, signaling, becomes a simple matter of inserting the desired gizmo in a circuit that is already there. It also makes finding that elusive short circuit a LOT easier. When you can loosen one wire and the overload lamp goes out, that leaves only a comparatively short length of track to microexamine.
My layout is a double garage filler. My longest continuous, ungapped, track is about 18 feet long and has one turnout. Imagine trying to find a short circuit somewhere in several hundred feet of track with a hundred or more turnouts including a couple of puzzle palaces. YOU imagine it. I don’t have to!
As for the lighted cars - I run common rail DC, and once considered installing a center line of stud contacts, Marklin style, to power car lights. That was before LEDs became common and cheap. Now my thinking runs to LEDs, with batteries recharged from the rails so the lights don’t go out when the train stops. If you want some extra complication, you could have the cars recharge from some form of connection at station platforms and storage tracks and divorce them completely from the track power. IMHO, that seems too much like work…
Chuck (modeling Central Japan in September, 1964 - with LOTS of lighted passenger cars)