I've a friend who rode her bicycle (yes you read that right) last year from the north shore of Alaska to Ushuaia. Solo, in her late 50's, cancer survivor. Her experiences were amazing, with so many friendly and helpful strangers whom she randomly encountered.What's next for adventure? I want to go to Ushuaia. We saw a few people in Alaska who started there, I'm jealous!
There were a couple of areas she had to stay away from for safety reasons. So if you do the ride be sure to carefully research which areas you should avoid. I believe one place was in Columbia where it borders Panama. Take seriously any such warnings at the time you travel! She also felt unsafe camping alone in a few places and chose to go to a hotel, though she did camp out most nights.
Ewan McGregor and Charley Boorman are reportedly scheduled to make the ride south to north next year for their next adventure, "Long Way Up".