The normally accepted solution is to extend the ball with a hitch extension, but extending the trailer tongue instead does have some advantages. Or you could do a half-and-half solution.
If extending the tongue, make sure that nothing else (jacks, plumbing, etc.) extends below the camper which you could wipe off with the tongue - including in situations like service station ramps which will pitch the truck up. Make sure the tongue extension does not have tongue jacks, or other paraphernalia close to the coupler. If it has a surge brake make sure you account for that being compressed backing up which will lessen your clearance (ask me how I know about that one...).
You can measure from the ball to the corner of the camper (or jack, if further) and if the tongue is long enough to clear that, you can jack knife the rig. Being sure to allow for backing and truck climbing a ramp (which will bring camper and trailer box closer together at the top).
I have lived with a trailer that does not have sufficient clearance. Enough for normal driving but if you crank the wheel hard over and turn continuously the trailer box will eventually hit the jacks. I put a mark on the trailer box indicating this angle which just comes into view in the side mirror when I am close. But it is perilous business, so easy to miss with the distractions of maneuvering in tight spots.
