In reply to Martin Thomas:
Reasonably simple if potentially expensive:
Train to Strathcarron/Kyle, ride round Applecross - Gairloch - Ullapool - Coigach then follow the NW until you need to get back. Several options back to a train at Lairg; Oykel Bridge road, Loch Shin road or if you are going well, round the top and back down via Altnaharra.
It's the best riding on these isles, 95% on quiet roads and i'm sure I don't have to tell you about the scenery.