I had the great privilege of being in a support crew team for a friend's effort at Oxfam Trailwalker in the weekend. I didn't get much sleep, spent alot of time driving...and also a lot of time waiting, thinking and taking photos. It was absolutely fantastic. I got so much headspace time, thinking about life, the universe and everything. I met some great people and had some very interesting conversations.
If you ever get the chance - do it. Even if you don't think you're up to walking, be part of a support crew. there is nothing like it.
PS - i'm actually thinking about walking it next year. Mad? yes!