I went to Iceland last January. Awesome place!
for Northern lights I did take a tour and I will say it was well run, fun tour and I have nothing bad to say about. However, it is true even the faintest green is seeing them. In fact, I couldn't even really see it with the naked eye, but the camera picked it up. so I was able to get some shots. The other point is their objective is to see them and in our case we were in a big empty field (read no foreground) not too far from the city (read light pollution to deal with) so while I have some pictures they are not catered to a photographer (unless you find one that is)! I did take a picture that night of an abandon house in which I was able to over lay the lights to give me something but like I said not wow.
If you can read up and plan and get your own car, you will have a better shot to what you want.