^ Yeah, it's pretty much only good for pistols and shotguns, and less than 100-yard rifle shooting. But you can shoot right there, in front of the kiosk/bathroom/picnic table, towards the hill that is away from the road. We've had BLM guys come out and talk to us while shooting there, and they said we were fine as long as we kept our muzzles away from the road.
I've also hiked back into that canyon you mentioned, on the left, and you're correct -- hills on both sides makes that area really only good for pistols too.
One of these days I'm gonna hike to the end of the canyon and climb those hills on the backside (away from the road) and see what is beyond them.
A lot of people don't see the abandoned mining shaft entrance there at Griswold, half way up the hill side, with a big iron door, padlocked to prevent entry (I've climbed up to it before just to see if there's any way to get in, but no).
I like to shoot my 1911 at that door from about 100 yards away. You hold at the top of the door and your shots will hit roughly center. THUNK! THUNK! Lots of fun (please don't shoot centerfire rifles at it though; that will dent and in some cases, penetrate; you don't want to damage somebody else's property). Doing this made me realize that the 1911 is plenty accurate to hit somebody at 100 yards, or at the very least keep their head down.
Griswold has a decent cinder block bathroom now and an improved parking lot, with a covered picnic table. These are major improvements compared to before (when there was absolutely NOTHING there!). Hopefully the thug/dumbass element haven't shot these improvements to pieces yet.
I haven't been out there for awhile.