A golf cart is 1,000lbs added to the front of a trailer even if it's in the back. ( that just means you have to pull car all the way to the front) 28' trailer with a car and golf cart is to much for a 1/2 truck. It's not just about pulling it, it's about handling the weight and stopping it.
I have a 3/4 ton Duramax and my 24'er loaded with cart and truck is about all it wants to SAFELY haul and it a 3/4 ton (with weight distribution hitch.) I'm planning to buy a bigger trailer so I ended up buying a dually and now use it to haul the trailer. Hope you're not pulling more than a few miles and on pretty flat ground. I've totaled 2 trucks and a trailer at less than 45mph because of using a 1/2 ton truck to tow a big trailer. Trust me jackknifing and flipping the trailer and truck on top of us in the tow truck is not much fun! Calling 3 tow trucks to haul tow truck, race truck and one to haul the trailer is not much fine either.