hi airperson and welcome to the forums...
are you dealing with david tidmore at rogerwilliams a/s in weatherford?
he will guide you to the best setup and he IS top notch for service and refined modifications.
NO ONE better in the dfw region or texas for that matter.
there are a few other threads on this low carry capacity issue...
search 'safari sport'
coloradobus was/is looking into ordering a until with higher rated axles...
the gvwr IS 4000lbs for a 3800lb trailer.
options aren't part of the base weight, but they have started to include a spare tire NOW so this should be included.
and NO NO NO you cannot subtract the tongue weight magically for more payload.
(sorry az') but this is misleading, like suggesting a w/d hitch increases payload.
it is the GVWR that is listed that is the limitation not JUST the axle rating.
all of the true things that i am about to tell you are shameless lies. l.b.j.
we are here on earth to fart around. don't let anybody tell you any different. k.v.