Yeah staying in Nozawa. Figure it's a nice base, small enough that there's no dull suburbs to cycle though, big enough to have things to do, places to eat, even in the off season, and can touch plenty of locations cycling, the nakatsu gorge you mentioned, shirane, and lots of winding roads around joetsu and tokamachi. Weather is looking good so hopefully it'll be fun.Rice fields are long gone unless your really high up.
Are you staying at Nozawa Onsen?