I’ve done some measuring on my bike and you’ll have done 2km if you bike from the Education Library to the other end of the walking/cycle path and back- in fact you don’t even have to go as far as Ilam Road- about half way between the tennis courts and the changing sheds should do it.
If you go to Reboot Cafe (fair trade chocolate bars, good range of vegetarian food- it’s a mini Cafe 101) and back, you’ll have done 2.5 km. Caroline