Find the German or UK international DVD release for original music. Region 1 DVDs have replacement music for licensing reasons, and it changes the show for the worse.
This is a whole thing tracked by r/northernexposure — apparently the version that was until recently included with Prime had maybe ~80% of the original music. And https://moosechick.com/ claims that the UK Blu-rays have all the original songs. More discussion at https://reddit.com/r/northernexposure/search/?q=music