We were stopped in Wall, SD on the 4th of July 2018 for two right stay (M-B Sprinter Class C had ABS/engine codes while visiting Custer SP, and we didn't want to be stranded on the highway on the 4th as the nearest dealer (warranty) was in Sioux Falls and 300 miles and 4 plus hours away. So, we bed down after dark, and just as we are falling asleep, BAM!... I thought someone drove into our RV. Nope... wind gust of hurricane proportions and wild rain and aligned with the slide side of our rig. Violent shaking went on for nearly an hour. To the West towards Rapid City was a southern horizon to northern horizon continuous (so it seemed) natural 'fireworks" show for well over an hour. Spectacular and we were fortunate not to be in the way of any flying debris or tree limbs. Never, ever seen so much lightning in the sky! Most of the intense lightning missing us to the west of Wall.
Limped away next day, with the codes clearing eventually, and as a result cruise control returning an hour or so on our homeward (east) drive on I-90. Just made a beeline home in NJ from there, except for a couple of hours at the AMA HQ and museum in Muncie, IN and the Wright-Patterson AFB museum (Spectacular!!!) near Dayton with two transiting stop nights in the process.
Scary experience for sure, and you were much closer to the "action"... but looks typical for out there this time of year! We were lucky to get only the "show" and no damage.
I doubt a lot of the RVs out there offer much faraday cage protection and I don't think we're anything other than fiberglass over a wood skin/frame. More TT's are metal skinned, methinks.
Always a pucker in a storm. Two years ago a mammoth cherry tree came crashing down in an early August storm while camping on the Eastern shore of Lake Ontario... missed 3 or 4 rigs... we were just beyond the upper canopy branches. No doubt fatalities would have ensued as the trunk was about 2 feet thick, and luckily it missed the campers by only a couple of feet as it fell perpendicular to the camp sites. no doubt there was soiled laundry in the adjoining sites!