Some quick checking indicates that the 2005 Armada towing capacity is more like 9000 (depending on specific equipment; requires optional tow package; check your vehicle). More problematic: It looks like it has a payload capacity of 1693 pounds (according to Edmunds; check your vehicle's details). By the time for you account for the trailer's tongue weight (could be 900+ pounds for a properly-balanced 6600 pound trailer), you'll rapidly run out of cargo capacity as you add passengers and cargo to the Armada.
While I couldn't verify this, it looks like the 2005 Nissan Armada has a rear axle rating of 4200 pounds; the Armada has a curb weight of about 5500 pounds. It's surprising how quickly you reach the axle limit figure when towing with family on board.
For reference, I recently faced a similar problem with a family of 5 and looking to upgrade our camping equipment. We opted for a 2005 Suburban 2500 (5500 pound rear axle; 2527 pound payload; 7600 pound towing capacity, a realistically usable figure even with family on board).