Have to disagree with Matt. Sandwood Bay path is very fragile and is held, I think, by John Muir Trust for good environmental reasons. Don't want to pontificate, but it's not the place for a 4WD.
For camping look at Scourie (near to Scourie Hotel for
s, and good fishing), Ardmair Bay near Ullapool, and for out of the way look at Stoer round the peninsula from Lochinver.
On the way north go over Bealach na Ba (sea level to 2000ft on one lane road with passing places, hairpins and superb view from top). Then go a few miles further on down to cafe just before Applecross village for good cakes and coffee. I think it's called the Flower Tunnel or similar. The drive round the Applcross peninsula to Sheildaig is excellent with good views to sea. Also an excellent bike ride.