We mostly camp in SP's also...inside the park, most of the time their roadways are clear for camper heights, have more problems with low limbs for the side of the camper and so far no close calls on the side roads leading up to the parks.
Some SP's websites will list a potential issue with the state roads leading into their park which is helpful.
Overall, just be aware of your surroundings and you'll be prepared...also look for signage on the small hwy roads that signal "truck routes", can't go wrong with those.
2013 Sabre 32RCTS-6 (sold)
Family of 4 whose always on the GEAUX!