I’d maybe suggest two (or more) places in a week (mainly as places there are small, limited facilities and so variety might help).
We stayed here http://www.ruareidh.co.uk/ lighthouse (very remote – treat for gf and my dad was a lighthouse keeper) – pretty good. Poss cycle round headland …….
Garvault hotel (most remote in Scotland – probably) generator power, deer in garden, one bike route but not on beaches. (basic, but brilliant experience)
Plockton – Haven hotel I think (okish)
KinlochBervie hotel (….. mmmm)
Coast road from Applecross to Torridon (in balzing sun to be fair) is the BEST I have ever seen (and I’ve done Britain) well worth a drive
Would suggest booking if near BH.
Just internet for accom we did.