More specifically from here or therabouts. From what I've read elsewhere it seems as though the path heading east up is pretty unrideable/cack, so looks like my best option is to ride back out to here and go somewhere from there…

Anything worth doing? What's good and what's cack?

Unrideable going east because it's very steep until you get to the watershed west of Camban bothy. After this point it's more (but not all) rideable towards Glen Affric but becomes boggier as you continue east. Coming back down to Glen Lichd would be a superb descent for the skillful rider (not me…)

I've only walked this so I'm surmising what it'd be like on a bike.

We did this ride in the summer. Started from the Countryside Centre in Morvich then headed east to the first of your points. We then continued east along the side of th Alt Granada before dropping into Glen Affric. We stopped the night at the youth hostel before heading back out west using the valley to the North, climbing over the Bealach an Sgairne before dropping back into Morvich.

The ride into the valley from Morvich is realy nice up to your first point but you'll be carrying your bike the majority of the way up after that:

Once you get to the summit it's rideable in parts but quite bitty and frustrating in places, the descent into Glen Affric is pretty uninspiring and there are a couple of river crossings that might be interesting at this time of year.

The climb back out from Glen Affric up to the Bealach an Sgairne was very boggy even at the end of May and you'll be carrying your bike for the last section.

However, if you can put up with all of that the final descent back into Morvich must be up there with the greatest trails in the UK. absolutely awesome:

For a lot of people I think that the amount of time you spend carrying your bike and pushing through bogs would make this a real waste of time but if you like exploring and gettig out in some stunning scenery it'd be pretty hard to beat. For me it was two of the best days I'v ever spent on a bike (althoug the stunning weather probably helped!)

More pics here