First time I plowed my garden I used my 20HP MF with a borrowed double plow. It's all I had at the time other than a little Troy bilt tiller. Since then I found it's better to take one of the doubles off so I plow with one. Sometimes I'm only on the back 2 wheels, but that's what brakes are for - steering.
Now with my L3130 I can use a double without knowing it's there.
Also, as someone else mentioned, when I didn't want to hook up the plow for a little bit of plowing, I have turned the dirt over with my loader. It works very well. Helps to take the grass off first so you don't have to chop it up.
Also, an inexpensive cultivator makes a decent tiller once you have plowed once. Once you have a plowed area, you can actually just cultivate it after that to prepare the ground.