Unfortunately, we never made it to the thermal water. As such, I can only review this place based on what we got to see. My advice, rent a horse or go by car. You don't want to be turned away, 3k after you pay the minor fee because there's no time to hike in (2 more kilometers ) and back on foot. Be sure to get an early start if you do.
The disappointment to me, however, was pretty minor. I just enjoyed being out in nature and the adventure of... not getting lost. If you want to take the bus in from Guadalajara it's about an hour ride. Cross the street/higway and stay left on the little road near the restaurant the whole way. You'll probably put 7k on your boots to get all the way there if you don't get horses. (My son is still afraid of horses after a trip to the Dells a few years ago. So, we hoofed it.)
I highly recommend getting to at least one of the natural areas when visiting Guadalajara. The terrain here was pretty easy walking, and we did enjoy our selves even if we didn't get all the way in. read more