Always been thinking of doing these two hills from Loch Lyon cycle in. I think this is a better approach than walkhighland route which I followed the first time I did this two hills two years ago and was not a pleasant outing.
The profile above is only the walking part. Cycle part is about 50 minutes 7.45k each way, around 50 ascent and descent, very good track all the way not much up downs. A few rivers to cross, not a problem usually. Fab scenery along the loch.

Started cycle in from south end of loch Lyon dam around 7.45k, reaches a big bend and a big river crossing (Altt Fionn a’Ghlinne) before a gate on the far side. The river is impossible to cross without wet getting wet after a week constant rain, it’s 1.10m deep nearer the sourse side, the right side is shallower but water flow too fast to commence a safe stable cross. There is a FB marked on OS map 100 yard north. but I did not go down to look the condition of the bridge, maybe next time.
Parked the bike before the river and start walk straight up Stob Garve-Leachtir, looks steeper than it is, really easy going. Then follow the ridge to Beinn Heasgarnich Summit. View would been amazing in a clear day but was in heavy rain and high wind up to 40mph from the summit and the whole ridge, very exposed to wind no shelter. Cleared up half way down the bealach. The rest route follow walkhighland route to Creag Mor. Much better view as now clear sky and dry, still quite windy at summit, didn’t stop long, only a few photos then carried on. There’s options, could stay on the ridge over Meall Tionail and down to the bike. As river so high we decided to go down the gully to east side of Altt Fionn a’ Ghlinne and follow the river down to the bike, the terrain is so much better than I expected, the valley is beautiful, looking down there is one section looks like a small version of the Lost valley in Glen Coe.

A pleasant nice route, would certainly recommend.