Mom, Dad, I found where the Summer of Love went!
It's precisely the sort of place that a fifty-something boomer would come to "get away from it all and re-center" alongside the 19-year-old who wants to smoke pot in a beautiful mountain town. To be clear: I'm not complaining about it at all -- the town is absolutely beautiful. The only downside is that it's the low season so almost every single bar closes down at around 9pm.
I think my parents would love it here. They once asked me if they would prefer Vietnam, Cambodia, or Thailand. I'm pretty sure the answer to that is that they'd like _northern_ Thailand the most, Especially Pai. Mornings and evenings at adorable little restaurants that run from tacos to Thai food and back again with daytimes spent cycling (or motorbiking) in the hills to all the hillside temples, waterfalls, hot springs, and elephants. Or they could go on multi-day guided treks or overnight rafting trips.
The only downside is that you could get a little bored with the town after a week or so if you need activities outside the natural beauty and a bar or two. Especially during the low season.