I just commented about this a bit above, but you've reminded me of a blog post I read years ago: "Why Norwegian is the easiest language for English speakers to learn" http://www.pagef30.com/2008/08/why-norwegian-is-easiest-lang...

I can't speak for Danish in particular, but I know the Scandivanian languages are all fairly similar. I know a little Swedish and am learning Norwegian and don't find them to be any harder than Spanish.