Tim just use this as a example because my truck is different. See the listed truck and RV below.
With current trailer loaded tongue is is around 950 lbs checked at a scale. . My truck tires are rated at max. load rating 3740 lbs each. Pulling the current trailer, I did attempt it with 55psi in rear tires and they where to low. The tires when looked at showed that they where low and the truck rear swayed. At 65 psi it is great. I have carried real heavy stuff and I needed 80 psi it the rear. Empty 50psi is fine. Just getting ready for a long trip and airing up the rear tires today.
2013 24RKSWE (27ft TT) Cougar 1/2 ton series
2013 Ford F350 4x4 CC 6.7 engine, 8 ft bed 3.55 rear end lariat package
Retired from Oregon State Police in 2011 than worked another 9.5 years as a small town traffic cop:
As of 05-2020, I am all done with 39 years total police work. No more uniforms for me.