Which is safer? There’s no hard and fast data for an objective comparison. Everything is subjective and swayed by personal opinion.
Most class A motorhomes are above the weight limit where crash tests are required. The fear is that things in the house become deadly projectiles no matter how secure you are in seatbelts/whatnot. But, being the bigger vehicle in most accidents, catastrophic wrecks aren’t the norm.
Trucks ARE crash tested, but not with a 10-25,000 pound trailer attached just a mere 3′ behind the passengers in the back seat. Less stuff to fly around, but 2,000-4,000 pounds of weight are a mere 3′ behind the passengers in the back seat.
Some people aren’t willing to accept the risk and move the family into a second chase vehicle and make it a moot point.
At the end of the day, you have to make the choice that you’re the most comfortable with. Good luck!