Don't linit yrself to "by cruise ship" type books. Get some on the specific area/country. I have done this for our last 2 cruises and we made up ourown tours by hiring a car and english speaking driver for what we wanted to do. Also asked for suggestions from the driver. Just be sure you can understand each other well enough and you know what it will cost up front. If you add or change and run more time be sure to add to the compensation accordingly.