A little bit over a year ago, I quit road cycling, left my road bike in my basement, and got back on my comfy upright 3-speed. Now I only cycle for transport around the city (purely recreational rides happen about once a month.) I still get in an *average* of 20 miles a day and on a 50+ lb bike that's a lot of exercise.

So the moral of the story is, even if you give up on road cycling, you can still have fun with other kinds of cycling.