Spindrift, Lismore can provide plenty of interest with ruined castles, seals and if you are lucky porpoise, as well as the scenery. various options for food depending on standard / expectations. BUT beware the tides around the south of Lismore kick up quite a mess and if the wind is blowing it can be "interesting" and if the wind and tide are fighting each other it can be "unpleasant".
Loch Etive provides shelter in many winds (but beware the falls of Lora).
Kerrera is rather pleasant and bizarrely quiet given its proximity to oban. Following the trail of teapots to the tearoom may entertain the family depending on their interests/ages!
If the weather is good then it really just depends how far you want to go - seil/Easdale, luing etc... have a look at some of the Gurnard's threads for all of this area as he includes both the details and some back story that can entertain the family....