That's what you should evaluate. You could do an informal survey, simply asking questions before the tour starts. Or send your guests a simple survey to fill out and bring. Or give it to them while you are driving to the first stop. Then follow up at the end of the tour with a similar survey to measure any changes in responses.
Evaluation comes in many forms.
The formal evaluation gives data upon which to make decisions. Other Methods Decision makers could be invited to any educational event, and they could be given a role in the meeting such as keynote speaker or panel member. Obviously, the decision maker should receive proper recognition for participation, including media coverage. Selected newsletters, clippings, and other information should be sent routinely to decision makers. Success stories, copies of letters of praise from customers, and news of staff awards are helpful.