The ACTUAL hitch wt must be at least 10% of the ACTUAL trailer wt. If fully loaded, this is 380 - 400#, not 290# shown for an empty trailer. If the hitch wt is too low, you will likely have problems towing, like excessive sway and porpoising. NOT FUN!
If you can pack extremely carefully and keep the gross wt of the TT below about 3300#, you should be within weight limits.
One other very critical weight is the total weight of the fully loaded van. You will find TWO labels on the driver door and frame. One lists tire sizes and the GVWR for the van. The other on the door latch post shows the "max weight of all passengers and cargo shall not exceed XXXX #"
This number is specific to YOUR van as it left the factory, including all optional equipment. Add the weight of all passengers, all cargo carried in the van, 50# for a WD hitch and 350# for hitch wt. This number must be less than the "max wt" label.
Note also that anything carried in the van counts against your payload, pound for pound. If those items are in the camper, they increase the camper weight pound for pound, but only 10% of that weight is carried by the van. This becomes a carefully orchestrated balancing act to keep all weights within limits.