Dear Ageless Traveler, Several years ago, on a Danube cruise with Theatrical Adventures at Sea, I met a woman whose husband had passed away five years earlier. She told me this was the first time she had the "guts," her word, to travel by herself. It wasn't a revelation to me. My own mother spent much of her life alone and never traveled until group tours began welcoming solo women travelers. What a difference a decade makes. Today, solo travel is all the rage, and it doesn't necessarily mean...