I did a few years ago. It was amazing. I went in early November and the weather was perfect. My tour company was Valencia and they did a great job. My best advice is to get into good cardiovascular shape. It’s only 26 miles over 4 days, but very strenuous miles, up and down. The high point - Dead Woman Pass - which you reach on the second day, is almost 14,000 feet. Two people in my group got altitude sickness. But most of us were fine. It’s an experience you will never forget.