A steady climb then a long descent to Durness, the most northerly point of the route.
These are not quite the biggest mountains in Scotland, but there is no easy option of just following the glen. The Atlantic coast is pierced deeply by the sea with fiord like lochs and the road climbs to get between them.
The mountains themselves may seem huge and bleak, but between them lurk oases of fertile soil and greenery in places like Durness, Laxford Bridge and Scourie. Local limestone outcrops account for this and these sometimes produce interesting caves like Smoo Cave near Durness.
There are also some fine beaches. You can walk or possibly mountain bike to Sandwood Bay. This two mile stretch of sand might have perhaps two other people on it. There are other fine beaches too around Durness.
Even if you never leave your bike you are sure to see plenty of sea birds. The sea cliffs, islands and stacks are filled with birds. A good way to see them might be to cycle to Cape Wrath. The highest sea cliffs in mainland Britain are here: 920 feet.
We continue north-east, heading towards the junction for Kinlochbervie, inevitably with another climb. There is a hotel at the B801/A838 road junction. Going to Kinlochbervie is a six mile diversion. Early on you pass the food shop London Store. Obviously the proprietor doesn't stock everything you can buy in London but he's certainly made a good attempt - probably cheaper than Harrods too. There is also a restaurant and B&B nearby at The Old School House. Kinlochbervie is that rare thing, a thriving fishing port. There are quite a number of B&Bs. If you continue to the end of the road beyond Kinlochbervie you'll eventually find a camp site at Blairmore (no shop). Going to Sandwood Bay is a fine thing to do. The first two thirds of the route would be easy enough to ride on any bicycle, after that it gets more difficult and you'd probably be best to walk unless you really like a challenge. Sandwood Bay is a two mile stretch of beautiful sand with Atlantic rollers pounding the beach. There are rock pinnacles - altogether a remote and lovely place. The final section to Durness is a lonely stretch of road with fine views of the quartzite ramparts of the mountain Foinaven. After this there is a long descent to the sea at the Kyle of Durness. You can cycle to Cape Wrath from here, an intermittent ferry takes you over the Kyle (see other route). After the Kyle there's a short climb then you are in Durness. Durness is strung out along the cliff top. There's a tourist office, a youth hostel, and a supermarket. More interesting places to visit are Smoo Cave and Balnakiel Craft Village. Smoo cave is in fact three caves, to get beyond the first cave you have to use a boat and pay. Balnakiel Craft Village is not particularly attractive from the outside as it consists of a collection of concrete huts (the leaflet says: imaginatively converted from a military base). Inside though you will find potters, weavers, enamelworkers, leatherworkers and other crafts' people. There's also a coffee shop with home baking. Durness is surrounded by attractive beaches, the best are just east of the village.
For the other parts of this route, click Related above.