Depends which islands. Madeira is usually a short walk to Funchal. Sometimes you can catch a ferry from ship to Funchal. About 5 minutes only to cross. Santa Cruz a short walk, busy traffic. La Palma would go on a tour. Lanzarote usually put on a shuttle bus to town. Would take a tour though.

The short answer is ....Very. This is assuming that you have done the preparatory work at home. and the best way of doing excursions, in my opinion, is with your fellow passengers and enjoy their company and the bonus of sharing expenses. ... Neil