Related, but not specifically your case. I used to drag race a 70 Camaro. Typical back half ladder bar car, full cage and 14x32 rear slicks. Ran high 10's, so not too radical. I had only wiring for ignition/fuel pump, start, tailight (so the tower can see when you pull off the end of the track at night) and elec water pump and fan. The car was set up with an alternator to help keep the battery voltage up high throughout a run and day at the track. So that was already wired in with the battery in the trunk.
Well, I got this crazy idea to make the car a street car. As I had a full fiberglass front end and doors, lexan windows and huge slicks, it was far from a real street car. But i digreess, back onto the subject. I decided not to add headlights, so it was daytime only. I added a simple fused wire through a brake switch to both tailights for brake. Wired both together, did not have turn signals, remember that I had no lights on the front? That is it, no other wiring was added. Still used all the race wiring. No turn signals, no horn, no wipers, fixed windows that did not roll down, one seat with full safety belts, slicks on the street, quite loud and super low for a street car.
Now I did add mufflers, simple extension off the headers and turn out before the rear tires, and would pump the slicks up to 10-12 psi for the street. I ran about 6 at the track. That car was so much fun driving on the street. The Cinderella nightime curfew kind of sucked. But I tell you that driving it on the street was a way to enjoy the car a lot more than just at the track. Since the car was 25 years old at the time (1995), in KY where i lived you could get "historic plates" for any vehicle 25 years or older. So that and some serious lack of detail to my insurance person "Well it does have an engine swap to a 454 and some aftermarket wheels..." I had a legal registered and insured vehicle to drive. I even had a bet with some guys at work that I could drive it the 20 miles to work and home, I did it and proved it was streetable.
I would encourage you to do it, just use your existing wiring and add the supplemental circuits you need for street. No need for a duplicate system. To my way of thinking that just adds an unneeded layer of complexity.
With all this talk it makes me want to consider making my 55 Stude project to be street driveable, notice I refrain from the exact street legal term, hahaha.