Camped many times at Fairview Riverside and Cajun Palms, and so somewhat understand this humidity thingy
What I found on a large 5er was to
close all blinds on the drive out to keep sun out, (maybe even get some reflective panels)
open the roof vents before getting there
to let it 'exhale' while going down the road...
then when there, plug in first thing and get ac going, (DOOH !
we kept the slides in to cool the least amount of space until it cooled off...
on ours we had an ac vent distribution system that we basically closed off at first (didn't want to cool roof panels until we got the inside air cool first!)
on our ac there where down draft louvers we could adjust/open and the cold air dumped straight down into the rv, not thru the ceiling vents...
that's how we did out best... let it cooled down and go have a beer either in the idling diesel truck or in the friends cool rv !!!
With the new (to us) mh, the 10kw generator is going before we get there and all 3 ac's are blowing cold so MUCH nicer !