I stayed there two winters ago.
The road noise is pretty loud. Not like you can't sleep, but for the length of time you drve to get in to the main campground, it's disappointing to end up perched right above the freeway. Also the campsites there are extremely unlevel and rough.
There are two sections of campground, though. I was in the one to the west, up above the freeway, which is a 30 or 45 minute drive in.
The other one is to the east of the freeway and I think lower down. I didn't choose it because I thought it would be noisier, but having experienced the upper campground, if I stay again I would try the lower. I'm thinking now that the road noise is probably the same in both places and the lower one is not such a drive in. I mean, if I'm going to drive 45 minutes off the freeway I would rather go somewhere more remote :-)
OTOH, I was just there for an overnight, and it would be more fun to stay a couple of nights and climb around on the rocks and stuff, and those are in the upper part. The lower part might have river access, I'm not sure.
There are bear boxes, and I don't think there are showers. And, yes, it is cold. It's quite high altitude, in either section. I was there in mid-october and it was well below freezing, though no snow yet. That was a drought year.
