It's pretty well all conventional wiring it's just canbus is a controller/ecu function that administers all/most electronics are working correctly..
I've got full canbus in my astra and have put in an aftermarket headunit and a canbus adapter so steering controls still function (the display shows nothing related to headunit anymore but) and I do get an error when I plug the car upto the computer just telling me it couldn't locate the "front entertainment unit" or whatever Opel called it.. It's had no effect on electronics in the car but at all and works fine.