We stumbled onto Surprise valley about 8 years ago. We were coming up from Gerlach NV and it was running late so we planned to camp in the Cedar pass campground. We stopped for gas in Cedarville and saw a sign for the hot springs. The sign needed a bit of restoration so we asked if the hot springs were still operational. Told they were, we headed on over. What a find. It wasn't so popular then so there was plenty of room. We've been back several times since, but last year it was booked solid and long term planning for us is a day or two at best. The room decor is, to say, not typical. Each room is different with an odd somewhat rustic western decor but not overdone and not particularly kitschy In our last room was a large painting of bears dancing and drinking - I think each room has it's own unique painting.
About 2 hours north is Summer Lake Hot Springs Resort on Summer Lake OR. Also a great stop, although it too has become quite popular in the past few years. They have cabins, dry camping, RV sites with power and water, even a house for rent. New owners have upgraded and repaired the springs. A few miles away are the Paisley caves which have yielded strong evidence of human habitation over 14,000 years ago.
(Gerlach is an interesting quiet place about 9 months of the year - and it's not the summer heat that ruins the other three months.)