We are planning to go to Scotland the first week of may. We will be renting a car from the Edinburgh airport and following Rick's 7 day guidelines more or less. The question i have is where in Scotland is a really cool place to star gaze?
Check out the best sites at darkskydiscovery.org.uk.
Of course, you need a cloud free sky, so you may or may not be successful, depending on the weather.....
There are a couple of dark skies parks in Scotland as noted. It depends on the route, but outside the Glasgow and Edinburgh area the night sky is generally clear.