Honey runs with me (well, to be truthful....runs in front, in circles, ahead, behind etc!!!)
I do a max of 5k at the moment.
I have a couple of routes. One is on our Country Park area where she can be completely off lead and she loves it. I run the circuit * 2 and she runs along with me.
If that is really muddy, then I do a run around the perimeter of our estate. For that she has to be on-lead. I run with her on her 5m extending lead. And we now have it down to a fine art. If we approach a lamp-post she knows she has to come 'this-way' so we don't get tangled etc
I am sure Honey could run much further...but alas I am just building up my fitness levels! She gets very excited when she sees me putting my running shoes on