I have never stopped overnight anywhere except a campground.  That is the reason I put up the orginal post.  I wanted to hear from those of you that do use other places.  I do not like going into a campground late, and possibly waking people.  
I live in North Carolina, and it is my understanding that you can not stay parked at a rest stop for longer than 2 hours.  
I understand that even though a truck stop would be more noisy, it is probably a relatively safe place to park for some sleep.  I guess one reason would be because there is more activity there.  I did stop late one night at a truck stop for fuel and a snack.  I saw what appeared to be a "working lady" knocking on the doors to some of the trucks there.  I would hope that she would not knock on the door to any type of RV since there is usually a family inside.