From zero to 5K is not very easy/practical though is it?
Yes it is. It takes time and builds you up slowly. When you get to 5k you can keep going if you want to see how far you can run - you just follow the pattern, or keep it at 5k.
@Will Triffitt I think @PinnerPaul was talking to @Mintyref about going to parkrun and going from running 0km to 5km in a day