Most JDM diesels are run for short, slow trips. This leads to incomplete combustion and deposits building up in the engine. Diesels like long, hot trips - not too hot, but hot enough to burn out the deposits and get proper complete combustion.
In your place, I would go equiped with the Baldwin BD7029 filters or better yet, the Toyota filter they are a copy of: 90915-30002, and after 1000Kms or so, stop and put on a new filter. Do it again after another 1000. This will help to remove a lot of the build up in the engine and free off your rings - which are probably sticky, if not stuck.
I'd been told about glazed cylinder bores but never saw the difference until I loaded my old NA market turbo diesel pickup and drove it over the mountains with a ton in the back. The difference after that trip was amazing. I really believe I got the glaze off and the rings properly seated on that trip as never before. I run a Frantz Filter so I know the oil is clean for a diesel of that age and condition, thus I conclude the difference must have been the glaze coming off the bores, rather than the rings unsticking - I'd noticed that happening long before.
Therefore, I would put as much weight in your truck as you can when you make the trip. The harder the engine works the better as long as temps stay where they should.
Get your cooling system flushed and pressure tested first. Get it in writing that there are no airlocks etc.
It goes without saying that your importer has changed all filters for new OEM ones and checked your fluids.
Just get it in writing before you leave.
The new Ultra Low Sulpher Diesel is causing problems with injection pump seals on some vehicles. Get a 2 gallon can of B100 bio-diesel and add a cup or two to every tank of fuel - more if you like. It does a great job of cleaning out your fuel system and will provide the lubrication lacking in ULSD.
Have a good trip.
