I would strongly recommend you go to
www.cruisecritic.com
and join up for free. On the boards on there you can find out about every aspect of cruising. You can join the 'roll call' for your cruise and 'talk' to other people on your cruise. Many of us organise private trips which usually work out cheaper and better than the cruise line tours. As with everything, there are pros and cons. The main one is if you go on a cruise line tour and you are late back (puncture on the coach etc) the ship will wait for you. If you are on a private tour, it won't. Now on all the cruises I've been on, its never happened, but just be aware. I've only been to 2 of your ports. If you are in your 70's, I don't think you would fancy the very steep climb to the old fort in Vigo, but there is plenty to see in the shore area. The most popular thing to do from Vigo is visit the cathedral at Santiago de Campostella (sp). At Brest we took a tour to Bayeux (and the tapestry) and then all the sites on the British and Canadian D Day beaches including the Mulberry harbour at Arromanches and the Pegasus bridge museum. Have a great time on your first cruise...personally, we love them!!!