Maybe - see https://www.usclimatedata.com/climate/denio/nevada/united-states/usnv0019 The campground altitude is about 300 feet higher than Denio. Denio Aug average hi is 90, low is 51 - it's a beautiful area.

Good for any time.

It would ok but HOT but there is a beautiful spring you can swim in

Yah, wouldn't be a problem, it's just pretty much all dirt, but has tables, one holers and i believe water faucet.. I wouldn't plan on too long a time, but a few days should be fine... and of course the hot springs pool...