An update to 'level 80 without riding'
I have made it to level 90 without level 20 riding through quest. I did each dungeon once through specific queue as to not get bonus exp. I only got a ride from someone with a 2 person mount once for 20 seconds to get to mists of pandaria ship.
Note: this was a pain in the behind
i.imgur(dot)com/YekfHfg.jpg