IMO the Icelandic light is itself a process and is hard to improve on! When we were there a couple of years ago, I shot JPEG and did pretty much no PP on most shots. We did pretty much the same as you - Southern section of the ring road to Hofn and back, with the Ice Lagoon and beach being my favourite area.
My only comment really is that a person beside the 'bergs gives a hint as to how big some of them are, as long as it can be done safely of course! From the lack of subject movement that your shots show, I'm guessing that they were reasonably big.
Did you see or hear any seals playing on the floes? It was too dark to shoot them when we were there but we could hear them singing at each other!