A lot depends on your towing experience, and confidence. Also towing that set up in busy traffic on the freeway could be a white knuckle tow, where a less busy state black top road at 55 may be okay. They do make after market heavier duty receivers, that may work for you.
Towing that size trailer, even with a 3500, at 70 mph in busy traffic would likely not be a fun experience, if you are new at towing a large trailer. You won't know until you give it a try. To be honest, many people on this forum will say too much trailer for that truck. Much depends on where, and how much you plan to tow.
BTW..welcome to the forum!
Jerry