* I spent a lot of time moving from city to city. Eventually, I learned that staying put in the same place for a month or more was the best strategy — but this was hard to do with Schengen travel limitations (as an American citizen).
* Finding housing was sometimes a pain (and expensive). Hostels were definitely a no-go: too loud, no personal space, impossible to get work done. Hotels were too pricy. Owner-listed rooms on Airbnb worked pretty well overall, but finding ones that weren't exorbitantly expensive ($35 or less a day) and that were rented out by people in the ballpark of my age required hustle. Longer house shares (often students living in a large house with a spare room) were the best bet, but finding them involved a lot of last-minute e-mails, phone calls, and even in-person interviews. (All this would have been much easier with a traveling companion.)
* Speaking of getting work done, I basically couldn't figure out a way to be productive. Towards the second half of my travels, I discovered that I worked best if the room I was renting already had a desk, chair, and window, and sticking to that requirement helped quite a bit. But even then, the temptation to go out and explore was often too great. Before then, I tried cafes, libraries, and co-working spaces, all without much success. I think I really need a stable place to call "home" to be productive.
* As a life-long loner, travel made my social life a whole lot worse. I barely talked to anyone during my travels, and neither hostels nor bars were of much use. I didn't really mind most of the time, but the fact that my only fulfilling interactions were over the phone did start to weigh on me after a while. (I felt the most social when I was living in house-shares with students, but those were only conversations in passing.)
I'd definitely travel again — it was a fascinating experience in the end! — but this time I would probably commit to staying in a single city for several months. I'd also try to find a large house (10-50 people) inhabited by people who share my age and interests.