moving to spain with cat, need info

Hi, me and my parents are moving to spain with our cat suki and we will be going down by car. We will be towing a caravan so that we can stay in sites along the way as we will be taking it slow down there. We will drive down and then a 1 hour ferry ride into france and then drive up to a site. We will be stopping every two hours which by then we should be at a site anyway. My cat suki will be traveling in the caravan in a large cat box, big enough to fit a litter tray and her bedding. If anyone has done this i would be greatful for your reply. Also if anyone has any information for me, that will also help.
thanx