There is a problem with a car using a radial tire and bias ply tire, as they have different traction abilities. So they would steer different, thus it is not legal to have a radial and bias ply tire on the same car or pickup.
Trailers are different, in that they are towed, and not steered, and no axle power is put to the trailer axles. For emergency use, I would not hesitate to tow the trailer several hundred miles. But I would also be looking for a tire shop, and change everything over to the longer mileage and higher quality (less likely to have a flat or blowout at 65 MPH) Radial tire.
Have fun camping!
Fred.
