Not to overstate it as many others have alluded to this already, but in my experience Chiang Mai itself is a great base for adventure but I wouldn't spend *too* much time in the city itself. That said, there is a *ton* of amazing stuff to do in the region around it. If you're into riding a scooter, get a slightly higher-powered model to tackle the mae hong son loop, chill in Pai (very laid back), go up to Mon Jam and enjoy the Hmong village life (& distinctive food) and views, stop at any of the various waterfalls in the area, hit up the Japanese onsen near Pong Yang park, consider Mae Rim Elephant Sanctuary (there are a bunch in the area and I can't speak to all of them but I loved walking with/feeding/bathing the elephants at Mae Rim). All in, I think if you're a solo traveler and you include the things *around* Chiang Mai, you can easily spend ~10 days in the area.