When our daughters were young, birth to preteens, we lived in Nenana Alaska and had a truck camper, a Class C bunk house model and a 35 ft. 5th wheel. Very seldom did we let the girls ride in the truck camper while on the road, but early on we only had regular cab pickups with a bench seat. Four people was a bit crowded. IN the Class C, the girls road in the overhead much of the time and we never gave it a lot of thought as to safety. My philosophy has always been to not have an accident, whether driving or flying my airplanes and so far it has worked. I have over 3,000 hours of Alaska bush flying experience and we made, I believe, 6 round trips from Alaska to the lower 48, usually to Florida where my wife's parents lived. Not sure why the idea of the girls riding in the overhead of the Class C seemed OK but not so much in the TC? Must have been, we could see them better in the C.
Would never have allowed them to ride in the 5th wheel when on the road. But we soon set it up permanently on our lot on the Kenai River just upstream from Soldotna. We would then use our TC/truck to pull our jet boat down to fish and play.
Probably why families used to be larger in numbers, get that heir and a few spares and you didn't have to be so careful. LOL I still remember riding on the front fenders of my dad's pickups as we drove down the back gravel roads of rural Oklahoma where I grew up or started growing up. LOL
I know I am a lot more careful now with my grandsons than I was with my daughters at their ages. But that goes for everything not just riding in vehicles.