You do have to have a cig. lighter receptacle that is hot when ignition is in ACC. If that isn't available, you can have a separate cig lighter receptacle installed that comes directly from the battery.
The brake buddy installation is something that you will have to do each time you hook up to the tow bar, not something that a dealer will do. Just follow the instructions in the initial setup and practice.
I leave my sensitivity setting at the very lowest setting so it takes a real panic to engage the brakes on the toad. You might find that you desire the additional braking of the toad...if so, I'd start at about 3 or 4 on the dial. I use 40 lb of pressure. I depend on the Brake Buddy more as a fail safe in case of an accident and somebody checks to see if I have an aux braking system and as a break-away stopping aid. 40 lbs will apply nearly maximum force to the brake pedal.
If your in doubt, wander around the campground and ask questions, you'll find a Brake Buddy owner who will give you a lesson on BB101. Good luck