Model that sleeps 4 adults under 5500 lbs or so

[slowmover]

There was no better full size to tow with in the 1960s70s than a unibody MOPAR. No ones launching with slicks.

And there was no penalty as to construction. Quite the opposite. Engine was lower and farther back. Vehicle had lower curb weight. Etc.

Get real weights of a proposed combination.

GVWR or GCVWR isn't realistic. Not if it puts one in a vehicle compromised versus a better choice capable of the job.

Some RV towing isn't going to break things.