The best way to use SideCar looks a little different for everyone.
You can use SideCar on your commute every day in traffic and long stretches of highway.
You can only use SideCar when you're taking a long road trip, and keep the harness connected. Your stock cruise control will work as usual when SideCar is disconnected.
You can move SideCar between cars as needed, just set up a harness in each car.