Nant Ffrancon round

Another 17 miler in preparation for Marathon Eryri but this time with an attempt to replicate its demands and profile more precisely. I parked in Bethesda and ran up the A5 all the way to Ogwen cottage in just over half an hour, felt OK but my HR was very high. I then ran alongside Llyn Ogwen to the Milestone Buttress, then back to the old road on the other side of the Afon Ogwen, the opposite side of Nant Ffrancon, all the way down to Lon Las Ogwen and the Slate Trail. Off-road and undulating to the Old Turnpike road and then a long extension through Tregarth all the way to the service station on the A55. Back up the draining climb to Bethesda. Still not long enough, but well over 1000ft of climbing.