I wouldn't even call 3N16 a stock route. You could do most of it in a suburu. It is the fire road that connects people to the actual trails.
I know I mentioned this before but you can definitely do white mountain in a STOCK 4x4 as long as you don't have low hanging running boards or nurf bars etc hanging down. The link below has pictures of a red 4Runner, completely stock, driven by my coworkers 17 y/o son. He made it though with no damage at all. I'm pretty sure we went from the east to the west which involved going
downhill on the toughest sections. If you go the other direction a locker or traction control could probably come in handy.
What I remember of white mountain, and keep me honest here GVL, is that there are NOT bypasses on the difficult parts of White Mountain. You can bypass the TRAIL White Mountain but it is a blue trail at the difficult parts and single road to the top. Again, it isn't bad at all. Go slow, get out of your truck, move some small rocks (yay lifting!) And it is a breeze. I'll try to find the pics.
Pictures from a black diamond:
http://www.toyota-4runner.org/1324234-post282.html #282
Pictures from White Mountain (Blue). No pictures of major big obstacles rocks because there were NOT ANY. If it's dry no big deal. Of course ice and snow can change things a lot. I'd definitely pack chains.
http://www.toyota-4runner.org/1420204-post302.html #302
There was one part that was a bit sketchy but common sense will go a long way to keep you safe. The most dangerous part (which I remember) is a downhill slanted portion of the road that has loose gravel and then a steep hill (not quite a cliff) on the lower slanted part of the slanted road. The upper part, keep in mind this portion of the trail is several vehicles wide, is solid granite. What do you do? Take the higher altitude side of the road, on the granite, not the loose gravel by the near cliff. Common sense will go a long way here. Easily avoidable.
