How do we pay our employees for both conference travel as well as time spent there?

Q: I am working on updating our policies and I think we are overcompensating for traveling to conferences. This is what we have been doing: The conference starts on Sunday, so we travel on Saturday. Our normal working hours are Monday through Friday from 8:00 to 4:00. The week before the conference, I give the employees a day and a half off, 10 to 12 hours. Then I give the employees a day off after the conference. I do this to make sure they are not working over 40 hours in a workweek. We count the time from when they leave their home until they reach their hotel rooms in the conference city, the hours they are in class and the hours traveling to their homes. We also take day trips 50 miles away for training on occasion. We pay for the travel time to the training, from the training and their meal. Can you give me some guidance on this issue? – Stephanie, Wyoming