Making a Cannondale BadBoy ride softer I have a Cannondale BadBoy with slick tyres, no suspension etc. On roads the ride is fine, but I do less of that these days and more along tracks (e.g. unmaintained paths, towpaths etc.). On non-metalled surfaces the ride is incredibly hard and I get incredible vibration through the forks and frames.

What are my options for modifying the bike so I can mitigate this. Will suspension forks soften the whole ride or just the vibration through the handlebars. My local bike shop recommended knobbly tires, a suspension-fitted seatpost and/or front suspension forks. Or should I just keep the bike for road use and get something more appropriate ?
Wider tires are the first thing to try. The BadBoys are basically rigid mountain bikes with 622mm wheels and narrow tires, so you could also put on mountain bike sized wheels and very wide tires. With a second set of wheels, it's easy to change between road and off-road riding.

About suspension forks, with current geometry there isn't much room for the suspension to work. You could install a 29" suspension fork, but that would change the bike's geometry.