Re the Cape Wrath road - It is rough and when I did it on a trike I found what with the grass growing in the middle of the road (about six inches to a foot high) and the width of the tarmac wasn't sufficient to take my two rear wheels so I alternated between bumping along with one wheel on the grass or on the verge. Also as you get nearer to the end of the road the headwind is quite some fink!
As the road just follows the terrain some of the wee climbs are hell of a steep. On one of the climbs I snapped the chain
All in all it took me about an hour and a quarter to cycle the ten miles.
Be warned the ferry man is very laid back chap and he also does life boat duty and as a result can be called away at short notice. When I arrived he was sitting in the boat with a group of four american tourists and a couple from Yorkshire. The Americans asked the ferryman, not unreasonably when was he setting off? To which he looked at the sky looked back at the americans and said "not yet as the van driver wouldn't be back yet". They asked when would the driver get back, "depends" says the ferryman. Americans start to look frustrated, and ask "can you radio the van driver with your radio?". Nah says the ferryman "The van driver doesn't switch his radio on as he doesn't like to be interrupted when he's telling stories to the passengers in the van". With that the ferryman laid out full length on one of the benches in the boat and went to sleep. The yanks waited a bit more but disgruntled they headed off. The ferryman having had a nice half hour kip woke and announced he would take us across.
Halfway across the firth he switches off the outboard motor and asks for the fare. A tad disconcerting, if we didn't pay would we have been thrown overboard? I can't remember what the price was for a passenger but I do remember he charged me a full fare plus half again as the trike had an "extra wheel compared to a bike".
By the time I got back from the lighthouse to the quay I just missed the ferry by about five minutes
So I had to just sit there and wait. My wife and kids had been to the beach but I had told them I should be back by about 3:00pm but as it was I had to sit there for another couple of hours until my wife had persuaded the ferryman that I would be waiting for him! As someone else said allow a day to get to Cape Wrath and back.
As for mossie repellant I use Skin so Soft to. It sort of works but if there are thoosands of the buggers then pedal faster and learn to ride without breathing and with yer eyes closed
I actually had to use this technique at various points when cycling from Corran ferry round to Glenfinnan as I came off the ferry at prime mossie time.