without knowing what size the engine is and what ratio the rear end is, i would guess, NO.
the fictional "dry" weight of the trailer is 5229lbs. add 400-500lbs. for options and batteries and you'll be at 5729lbs. now, subtract what the weight of the bikes, passengers and cargo in the van, from the 6400lbs. number.
you'll be at or over your max, if you have typical cargo and propane and water.
and it'll definitely struggle in the mountains.
by the way, NEVER believe the dealers. their job is to sell you a trailer, not to worry if your vehicle can tow it. there are too many stories about people believing their dealer until they try pulling the trailer and do permanent damage to their vehicle.