Specifically, the song is Genesis by Jorma Kaukonen. I couldn't find a good tab for it on the internet, so I started to make one myself. The key that I'm playing in is G and so far for the intro I start with a G chord shape, then an Em (with the last bass note being a G on the sixth string), then a C shape. So far, all I have is the intro. But judging by other tabs for it, I think it stays in G for most of the song.
But, as I'm sure you know, there are some notes in chord shape that may have to change... for example the one I just mentioned... where I have to add a G on the sixth string to the Em shape. Those are the tougher ones... where the shape will not look like any chord I've ever seen.
Could you clarify what you mean by "scale tendencies"? I'm somewhat new to playing music and I haven't gotten all of the lingo down.
A horse walks into a bar and the bartender says "Why the long face?"