I think that if you check you'll find that you can run a number of rounds equal to your Con<em>score</em>, not<em>modifier</em>.  I don't think anyone who could only run at their top speed for six seconds could call themselves "fit" much less an "adventurer" :P<br/><br/>Also, I'd only need to overrun them by enough to use Climb as a part of movement (clambering onto the coach), then I'm along for the ride.