In reply to OG:
Fiacaill is very weather-dependent - as Ben B says it could be intimidating for the in-laws if it's wet and windy, and of course takes you up to near 4000', so would be a bit speculative in November.
Depending on the forecast you might be better going west to Kinlochewe and doing the Beinn Eighe Mountain Trail -
http://www.snh.org.uk/pdfs/publications/designatedareas/beinneighemounttrai... It's steep and quite rough, but mostly sheltered from south-westerlies, gives fine views. Always a worthwhile atmospheric outing for short November days, or if the tops are in murk. Driving time similar to Cairngorm.