We've gotten in the habit of putting our GoPro camera on our dashboard and taking either video or a photo of the trip every 5 seconds. When we get home, Jimmy combines all those images, this time over 3000 before the battery died, into a video. Then I take it, edit out the long pauses when we stop and nothing is changing, do a bit of cropping so the car is mostly out of frame and finding music that's approximately the same length of the video and sort of matches the mood/theme/pace of it.
Here's our video from our Memorial Day Drive with our friend John.
click on the 'youtube' icon on the bottom right of the video to make it bigger.