I have the misfortune to have a bad knee. Although I've ridden all my life, by the age of 18 I was told to stop running track and riding if I wanted continue walking past age 40. As a teen, of course, I stubbornly continued to ride, although I did give up my dreams of being a Collegiate 300 meter hurdler. However, horseback riding was very painful, so I decided to find another outlet. Driving was the obvious choice.
I had a little bit of experience driving since my childhood pony did double duty as a riding and driving pony. However, my experience with her was very much one of trial and error--mostly error. My first attempt at harnessing my pony at age 8 could easily have been disastrous. Luckily, my Saddlebred-mix pony should have been a saint since she took all my attempts with good grace. Usually, my mother was a more than competent horsewoman, but she'd never harnessed a horse before either. Eventually we figured it all out and enjoyed hundreds of miles in the pony cart.
This experience of the end product of driving training helped with harnessing, but training a horse to drive was an unknown. However, I have always had a huge dose of horse crazy, so I decided to train my Quarter Horse filly to ride as well as drive. Due to my enthusiasm, my filly had been extensively handled since birth. As part of preparing her for riding, I was already planning on doing extensive ground driving. I figured I'd just build on that. Since I love to read and research I also purchased several books and scoured the Internet for how-to information. Much of the information found seemed to assume I had more money, equipment, and help than reality. Many also were aimed toward showing or competition.
None of the books or information were 100% applicable to me and my goal, so I decided to mix, match, and adapt. I know I made many mistakes and took chances not highly recommended. My filly was also not a breed well-known or acknowledged for driving. The "facility" I used consisted of an acre and a half pasture and nothing else. Yet, by the time my filly was 4 she was a safe and willing driving horse that would pull anything hitched behind her. As a matter of fact, by the time she was 6 we both preferred driving to riding--even on trails.
So if you have been told riding is not an option for you physically, you do have an alternative: driving. If you've been put off by the seeming difficulty of driving and the intricacy of the equipment, don't be. Use the horse sense you already have and pursue your horse crazy dreams behind your horse instead of atop your horse.