OP wrote:
The dry weight is 2,623 lbs
Unless you plan on towing it empty, then dry weight is meaningless. Do you plan on camping in cool weather? TThe furnace runs on propane. What the salesman says is also meaningless. He wants to make a sale.
Look inside your drivers door for the sticker and read the part that says something like total weight of cargo and passengers not to exceed XXXX lbs, and post that number.
The concern is not having enough payload - what the minivan can carry. Everything in it including the weight of the hitch you installed, tongue weight and all other cargo/occupants go against payload which will be exceeded before your tow capacity is reached.
Pulling a high walled TT down the road will work your engine hard. It might be good for very short distances.
Post the info I asked for to see where your at.