Also, as much as I love trailers with a tack room/dressing room up front, they make it very hard to load the trailer correctly with enough weight forward.
This trailer requires a bigger truck in *wheel base* and overall body length, not just in towing capacity. And it's the type of rig, because of the length of the trailer, that absolutely benefits from hitch stablizer or anti sway bars.
One final note: IMO and IME, anything larger that a standard length two horse going short distances locally requires a 3/4 ton truck. Dealers and people how don't haul horses will tell you a 1/2 ton will work. Don't listen. If you're going to do anything other than haul one horse short distances, get a 3/4 ton truck.
Also, ask for specifics on what the "tow package" is - dealers will tell you it has a "tow package" if it has a hitch mount and a connection for the brakes. A real tow package includes a beefed up suspension, heavy duty radiator and a transmission oil cooler.
Sorry to be the bearer of bad news, looks like an awesome trailer that I'd love to have.
PS - per Iridehorses - The emergency brake cable needs to run free of all other elements of the hitch. It's purpose is to lock the brakes on the trailer and keep it from rolling if the trailer breaks away from the tow vehicle. It can't do that if the cable is hung on another part of the hitch - the cable will break without pulling the pin and setting the breaks.
Safety chains need to be shorter, and I like beefed up heavier ones. You can cross yours several times or run the clip through the ring on the hitch and fasten them back to themselves. You don't want them dragging or throwing sparks.