I have biked for a lot longer than I have cached. and now enjoy combining the two. I usually use my mountain bike that has the GPSr mount on the handlebars, with knobby tires. The rolling resistance is higher than on my road bike, but I figure I am getting a better workout.
I did a series this past March near Cocoa Beach, FL along some off road trails, and the bike saved me lots of time.
The longest caching ride I have done was a 60 mile round trip from a campground in Virginia, up to Washington DC.
These days of expensive gas make a bicycle much cheaper to operate.