I had a chance to do this in my 20s. I’d somehow become part of the au pair (nanny) crowd in my hometown, and had become close friends with many of them, so I purchased a 3 month Eurail pass and a plane ticket and headed to Europe without a specific plan.
One of the best things I’ve ever done. I had a built-in set of friends over there to show me around, I made new friends, I improved my German, and I did oh so many amazing things.
Couchsurfing.com sounds a bit scary to me, given you’d be staying with people with whom you have no previous relationship, but this is the 21st century…I’m finding it’s easier to make friends with people across the world.
Given I’m older now, and they are like to be older as well, they likely have a guest room and not a couch, so there is that.