All kinds of ways to skin this cat.
You could also lower the truck with smaller wheels & not so tall tires. Another is the Lippert Correct Track system for compensating minor wheel alignment issues. Using it raises the trailer by about 3".
How about taller tires for the trailer. Watch out for rubbing under the slides or slide extending gear.
Getting a Carriage of that vintage I would not mind investing some extra money in it for the long haul.
Boat: 32' 1996 Albin 32+2, single Cummins 315hp
40+ night per year overnighter
2007 Alpenlite 34RLR
2006 Chevy 3500 LT, CC,LB 6.6L Diesel
Ham Radio: VP9KL, IRLP node 7995