If you are after a CMS that you can easily update when you are travelling I would recommend Wordpress. It very easy to learn how to use with no technical knowledge. We find most of our customers prefer Wordpress. For more complicated CMS we would recommend Joomla.
WordPress and Drupal are fine. Drupal has a lot more funtionalty out of the box. Joomla is complete crap.
Wordpress is great. Avoid Joomla. But I think that adding all functionality for travel site to existing CMS is equal to building custom CMS.