I have a 52 1 ton with a 55 model 235 as well, and an SM420, it was geared for about 53 mph at 2400 rpm.
The truck weighed 4,400 lb empty and had a hard time towing an empty 3,500 lb tandem axle flat trailer. It would haul 4,000 lb or so in the bed with some effort, but still very manageable. Somehow the trailer is a different kind of load, more friction or drag?

I expect you'll be fine with a light camper trailer.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-