A trailer that size is going to be a serious strain on the van because of frontal area, and may be difficult to control on the highway in any sort of crosswind or heavy truck traffic.
A lower profile molded trailer like Scamp or Casita would be better, but still beyond frontal area limits. A friend of mine towed a 17 foot Casita behind his Grand Caravan for almost ten years, towing carefully. It did eventually wear out the van.
You are not far from the Casita factory and showroom. Visit them, talk to. the sales consultant. Unlike the sales persons at many dealerships, they are concerned about the towing combination. "What will you tow it with?" was one of the first questions when I visited afew years ago.