Interesting mountains and wild scenery, narrow roads with passing places.
I took a group of Americans here a few years ago. They were experienced cyclists who had ridden widely in the USA, Canada and Europe. At the end they said it had been the best bike ride ever. Fortunately the weather had been kind as there are often long spells of settled weather in the early summer.
The area falls into two parts as far as cycling is concerned: Coigach to the south is not dreadfully hilly. Cycling this is inevitably out and back. A rough track is shown on some maps leading from the road end east of Achiltibuie to the A835 near Strath Kanaird. This is difficult scrambling and taking a bike is out of the question.
All the same you should go to Altandhu, Achiltiebuie etc. There are some lovely beaches combined with distant views of the mountains to the north. There are also interesting places to visit.
Further north in Assynt it's sort of hilly. A B&B owner in Lochinver once told me that she was expecting a family from Surrey one evening. They planned to cycle from Kylesku via Drumbeg. They knew it was hilly but it was only 25 miles after all. She got a phone call at 3pm in the afternoon, they weren't even half way round - she drove round and collected them.
As mentioned earlier there is a tea room at Elphin. There is also a Farm Centre which has over 36 rare breeds of farm animals, ancient and modern. This is a working croft which has been adapted for education, conservation and organic farming. It has a tea room too. There's a Scottish jewellery/lapidary centre just south of this. The A835 here is the main road to the north west so depending on the time of day there is certain to be some traffic on it. The road is reasonably wide and the sight lines are mostly good but there are some tight bends around Elphin. You will be on it for eight miles after which you turn right into Inverpolly Nature Reserve for Achiltiebuie, Lochinver etc. There's an initial climb then you drop down to Loch Lurgainn. This has sandy beaches and a number of islets covered in trees - once all the highlands were like this. A notice board opposite Stac Pollaidh gives information about the nature reserve; the mountain is a popular climb. Shortly after Stac Pollaidh you reach the road junction at Aird of Coigach where you have to take a decision.
For other parts of this route, click Related above.