Might also check into Camping World. Usually have space and are very welcoming - of course, they're happy if you shop, too. Absolutely, check with the manager or better yet, call ahead so no last minute surprises. No chairs or awnings, keep it low key. Sam's Clubs also usually have plenty of overnighters and honestly feel safer with others nearby. Remember, almost always, no hookups, so come prepared. Have never done the Interstate Rest Stops, but if they indicated overnighting is allowed, we wouldn't have a problem with that. We take a yearly spring trek to FL for spring training and overnight at 2 CWs and they're very accommodating.