I just finished a 14.63km cycle that lasted about 0hh:53mm:23ss !
I have been recently exploring new routs to keep improving my distance and also the climbing. The are where I live has a lots of hills so is either you find something like a circuit or you go up and then down because there isn't much flat land.
Check out some detailed info at my EXHAUST page
Join me in testing out EXHAUST!