Tried Rest stops for "overnighting" more than once, each time very little "rest" was had. Not fun having trucks parking beside you with engines idling all night not to mention the occasional reefer parking beside you..
I finally resorted to using safety ear plugs in order to get a few winks..
I personally try to avoid overnighting at rest stops, too much truck traffic in and out all night long.
I find mall parking lots, WM, Sams and such to be a bit better in that respect (not to mention they often have CAMERAS pointing in all directions so if something happens it WILL be recorded). Even then safety ear plugs sometimes comes in handy...