I did a route from Inverness to Tongue a couple of years back, the second half of which was the same as Ticktockmy's as far as Gobernuisgach.
The first half went up Strath Rusdale (starting near Alness, NE of Dingwall), past Loch a'Chairn to Croick, then up Strath Cuilleannach and over to Oykel Bridge. Turn right on the A837 for a few miles to Rosehall, where ticktockmy's route starts.
2 days, during which I passed 3 commercial establishments, all of which were shut (Oykel Bridge Hotel, shop & pub in Rosehall), between Evanton & Bettyhill.
On the return I followed the road route past the Crask Inn as far as Bonar Bridge, then went up Strathcarron to the Craigs and followed the track up Gleann Mor and down Strath Vaich to the A835. There were also forestry roads paralleling sections of the A835 towards Contin, but I didn't bother with them as I was running a bit late.
Another possible route that I've not tried is up Glen Achall from near Ullapool, and past Loch an Daimh towards Oykel Bridge (probably would mean a fair bit of walking past the loch).
There's also the possibility of a circuit of the Cairngorms if you feel adventurous and don't mind a fair bit of hike-a-bike (Aviemore, down Glen Feshie, across to Braemar, north via the river Avon to Tomintoul, back to Aviemore on the Abernethy/Rothiemurchus forest tracks).