I'm pretty sure those old Passports were basically rebadged Isuzu Rodeos.
So if the Rodeo was flat towable then the Passport should also be.
I know that doesn't give you a definitive answer but might help in determining the answer.
Come to think of it, the Owner's Manual typically gives specific towing instructions. If you do not have the Owner's Manual try looking on eBay for a used one. There are sellers that specialize in those things.
1995 Coachmen Santara 360MB 36' w/slide.
Ford F53/460 chassis, 1997 Jeep Grand Cherokee "toad"