Heavier suspension won’t add anything. The problem with a trailer this size is its shape. A squared edge box is no fun in crosswinds. It’s weight doesn’t matter. 4,000-lbs or 10,000-lbs it’d still have the same sail area.
My trailer is 35’. My truck a good match ONLY when it’s fully loaded so that FF/RR spring compliance accepts WDH loading well. Long wheelbase, high COG, narrow tires, ARE NOT aspects of a good tow vehicle.
That pickup cited is — like mine — overpowered for the job.
I use and strongly advocate the use of a Hensley patent hitch (that brand name or the improved patent Pro Pride brand). Eliminating sway (SUDDEN crosswinds) has no peer.
Anyone starts citing “weight” or payload really hasn’t a clue of what factors matter. WDH solved the problem circa 1966. STEERING & BRAKING are what matter, overwhelmingly.
The toughest part about a long trailer is in maneuvering it on & off highway. If a new experience, it takes time to “know” what will work, and what won’t.
An even LONGER wheelbase pickup just makes steering & handling worse, not better.
OP, the well-intentioned newbies with 10-20 years tend not to know much. Haven’t any experience but with badly hitched rigs composed of badly designed vehicles, and never investigate causes versus analyzing what’s really wrong. Then makes things worse with “a bigger tow vehicle”.
That pickup is more than enough. The details of RIGHT hitch rigging are what remain. Don’t exceed axle/tire limits is how it’s contained. It’ll then be the BETTER TV than a 1T.
Slow up a sharp grade? So what? So is every heavy vehicle. Being able to stop and steer well is BEST hitch rigging ON THE DOWNSLOPE. That’s where most vehicle loss of control accidents occur (wind gusts & slippery surface).
The rig acts best under slight positive acceleration where the WDH has spread the FORCE exerted by the trailer tongue LEVER end OVER both vehicles.
Compliant-suspension vehicles (trailer would need DEXTER TOR FLEX as upgrade) have it over stiffly sprung short wheel travel vehicles.
MORE spring capacity is the exact wrong direction of things important.
2004 555 CTD QC LB NV-5600
1990 35’ Silver Streak