Unless you already have a braking system, you might want to check out the Ready Brake line of products. They make a towbar with an integral braking system called the Ready Brute. They also have braking systems that will work with other towbars, like my Blue Ox towbar.
Their braking systems are effective and purely mechanical so they don't rely on electricity, electronics, or air, thereby reducing the chance of failure. They don't advertise as much as other manufactures like Brake Buddy and the like but the owners' reviews that I've read are pretty much 100% positive. The criticisms posted in various forums are invariably theoretical and posted by owners of other systems who have no experience with the Ready Brake. They're also less expensive and there's nothing to move in and out of your toad.
https://www.readybrake.com/