That picture of the little fw reminds me of my 20' Jayco. The Ford salesman told me that the 1997 F-150 with the 6 cylinder and tow package would handle the trailer fine. We got up to Black mountain SP in Georgia and there was this long hill inside the cg. We got halfway up the hill and stopped. I had the family get out (including mother-in-law) and backed down the hill, got a running start and made it up the hill. They were not happy campers.
Getting back to your question. I can see where a shorter fw would tend to put less weight on your pin, unless you were putting all the weight in the bedroom. I was looking at nada for your model and the 19' was about 3700 lbs. The 23' was 4200 lbs. I didn't se a 22' model listed.