Definitions:
Workshop: Designed to teach you, one-on-one, techniques and skills, in the classroom, field, or in studio. These lessons may include camera care, post-production and business, skills and techniques. Almost always, there is a critique of your photographs taken during the workshop.
Tour: Designed to take you to a number of locations at the best time of the day and year. The tour leader should know which locations will give you the best opportunity to take the best shot possible. There is no, or very minimal, instruction given on a tour.