Unless you are towing the trailer 10k miles a year there is not a lot of reason to rotate the tires. They will need to be replaced due to age (5-6 years) long before the tread wears out.
A vehicle's tires need to be rotated because the front wheels, that is the steering, puts a lot of extra wear on them. Rotating every 8k miles or so keeps everything even. And yes to the point above about cross rotation of radials. I have been doing this with my vehicles for many years.
Goodyear Rotation Recomendations
BF Goodrich Rotation Recomendations
. For this one, click on the tire types. Different configs have different recommendations.