I came across my new favorite hot spring last month and I shot a video of the 2 mile hike up a 1,300 foot snowy hill to the spring.
The trip is a bit of a challenge: my wife and I hiked through a storm starting at a highway pass, going over train tracks, through a forest, parallel to power lines, through another forest, and then into a winter oasis of warm pure spring water.
I've never seen as perfect of a setting for a hot spring. I've also never seen pools as well maintained.
Here is the entire video if you want to get a sense of the trip and get the planning details:http://www.walkifornia.com/2012/03/scenic-hot-springs-beyond-california.html