What an amazing experience! I'm glad that you find a place there with no tourists. I've heard many times that Iceland becomes overcrowded with tourists..
Your photos are amazing! I'm sorry for that always being wet part :) I would probably freak out if I would know that I have to walk another 25 km that I wouldn't know about. But well.. when you have to, you have to :)
Thank you for sharing and have a lovely day!