You can find the routes and the nearest dash details here. You have a choice between 2km or a 300m dash.
The route normally all starts in a pub, so you'll get a chance to brave up a little with a beer or two perhaps. You can come dressed in just about anything as it's ultimately all about fun and raising funds at the same time. Although they do have one policy and that is no undies please.
Please see their main website for more details and how to register.