I've put this out many times when this question comes up- A Toyota pulled the space shuttle! Yep. Many years ago, it was a stunt by the company.
For a safe enjoyable journey, you need to get a 3/4 ton truck for a start, either set up the hitch or have a "competent" dealer install it, and try to hook up with an experienced RVer for your maiden voyage.
It sounds like the dealership was only interested in moving the unit out but I can't understand why they didn't address the hitch--the the hitches usually are brought up early on in the sale.
Please don't roast me on this---but, in almost 50,000 miles of pulling a trailer, I've never seen a Cadillac as a tow vehicle. They do make a great toad behind a motorhome though.
See ya out there.