The winter is the best time for hot springs, the colder the better, ideally with snow falling. If you prefer to overnight, would highly recommend the CO river as an alternative three hours away. Plenty of hot springs and camp areas along the way given the prohibition on camping near the DCHS pools. Just need a canoe or kayak. We did it two weekends ago and it was great, even saw two bald eagles in a nest quite close. Can light up the walls during the night sitting in the pools too.