@Trip - I would not take the distance you run to be a badge of honour. I have seen so many referees run "miles and miles" in matches, thinking they are doing the right thing and all they are really done is covering up for the mistakes in positioning and anticipation of the play. Just ask @es1
Fitness does provide a massive advantage to developing as a referee, but you need to use it well and not just cover mile and mile running after the ball.
i'm totally with you @lincs22, fitness does not make a good ref, but it sure can help! a good confident ref can make accurate calls from 20+ yards away but the moment you start getting calls wrong your credibility is shot.
i speak as a ref who's definitely above average weight and below average fitness for my level