Ignore the idiots on the cycle path. Cycle path use is not mandatory, in fact most are so poorly designed and maintained that they are better being ignored.
Personally I go a step further and have a policy of NOT using them in any situation in protest at the waste of taxpayers money they represent.
Cycle paths north of Oban are generally good if you just want to have a quiet pootle and also wander a bit as well. For travelling from say Oban to Fort William they are pretty useless tho' the section of A82 north of Ballachulish is so bad trafficwise that the inadequate cycle path IMO is preferable.
These are the the only ones I have experience of since most of my touring is done on quieter roads and in the distant past traffic was pretty light anyway so main roads were no problem then unless at peak holiday time.
Just remembered there is one from Dingwall which takes you towards Muir of Ord but turns up the Inverness road and deposits you on the Black Isle. I have used that one often and it is pretty good. Wide and well surfaced.