Pin Box vs. Truck Bed Wall: How to Avoid Conflict?

When I bought my fifth wheel, it had an extended pin box. After dinging the rails on both side of the TV, I gave the extended pin box away and put a standard unit on the trailer. Now it is impossible for the box to hit the rails or for the front cap to hit the truck cab while making any normal turns.
Trimming the back of the pin box would have required a lot of steel to be cut off, though it may have worked.