Well...try Smith Lake.
Its a gorgeous little lake at the end of a 4x4 trail.
I don't fish much anymore so I can't vouch for the fishing, but the area is beautiful and very very remote.
Here are the coordinates
There is one OUTSTANDING and one good campsite there.
You can reach it by a few routes.
Take the Gold Lake 4x4 trail all around the lake, then up over the pass and down into Gold Valley. (Thats the way I went in), or
The road around Sardine Lake (paved), then up over the pass and out Butcher Ranch road to Gold Valley. (The way I came out), or
Sierra Buttes Trail out of Sierra City.
All three routes eventually meet up and take you into Gold Valley. Dropping down into the valley, there is one very short but very difficult section for a long wheelbase rig. I took the wrong line, became high centered and had to winch myself off the rocks.
Yup, that there is air under the passenger rear tire. I think the real cause was magnetic flux brought about by the SMB magnet on the front fender. I hear they are collectors items now.
As a disclaimer I must tell you I had a "little problem" while in the general vicinity (it didn't happen on the trail to the lake). You can read about it here. viewtopic.php?p=84356#p84356
We were in the vicinity last weekend (Poker Flat) and I would have ended up there, but the rain pushed us out of the mountains. Have a good trip, and if you find another secret spot let us know.