Looks like a good day out with the dogs. I went to see the Callanish stone circle on Lewis - http://www.stonepages.com/scotland/callanishhi.html
and also Carloway broch - http://www.megalithic.co.uk/article.php?sid=503
you should try and visit there when you are in Arisaig. The bridge to Skye is toll-free now and CalMac run a ferry from Skye to Lewis.