Cape Wrath
From the start of the track at Blairmore (pictured right) a ridable if difficult in places jeep track continues for about two miles to Loch á Mhuilinn. The track quickly deteriorates into a boggy sandy path mostly walking all the way to Sandwood Bay.
Sandwood Bay (pictured left and below) is worth going to even if you do not intend to go all the way to the Cape.
Pushing the bike through the sand is very hard work. Beware of the tides as you could possibly get caught out.
It is best to cross the river close to Sandwood Loch 225653. This is some 50yds wide here but very shallow.
There then follows a very steep scramble up what looks like a path. This is probably the most difficult part of the crossing. Once over the worst it flattens out and becomes grassy. Head for what looks like a wall on a rocky outcrop. From here navigate using the map and the tarns which can be easily seen one you climb up to the 100m contour.
There is no waymarked path to the Cape and there is nothing on the ground either. From the bay it is at least five hours of hard pushing over very boggy ground to reach the road to the Light House. I strongly advise you do not make your route too close to the coast. Try and follow the contours and keep your height.
It is best to join the road at 285716
Map of suggested route
There are plenty of high walls and out buildings for shelter from the wind.
The Cape Wrath Fellowship: There used to be a book you could sign at the lighthouse and for a small fee you could buy a certificate, however this is now run by the CTC (Cyclists' Touring Club).
If you want to join, send a picture of yourself in front of the light house to the CTC and 6.50 GBP. Mark the envelope The Cape Wrath Fellowship and you should receive a certificate with an impresive badge.
This information is now out of date but left for completeness. See the following footnote
Updated Info 
Cape Wrath Fellowship
Joining the Cape Wrath Fellowship [cyclinguk.org/capewrath] is now simpler than ever. Founded in 1949 (so predating the RSF by only six years) by Rex “Ragged Staff” Coley to celebrate and encourage adventurous cycling, the Cape Wrath Fellowship is now administered by Cycling UK (formerly CTC). To join the CWF, all is required is a photo of you and your bike at the Cape Wrath lighthouse which you can then upload along with your details on the Cycling UK website: https://shop.cyclinguk.org/cape-wrath-certificate
There is no cost associated with membership, and Cycling UK will send your certificate in the post (for free) acknowledging your membership
....and just get you inspired here's a cracking piece of video from our friends at Cycling UK