Soy nuts add a healthy crunch to this snack mix, but if you like, you can use dry-roasted peanuts instead.
Look for the yogurt-covered raisins in packages in your supermarket with the other raisins and dried fruits. Or you can sometimes find them in the bulk-foods section.
You can make this crunchy snack up to one month ahead of time. Store it in small resealable plastic food-storage bags or in an airtight container.