I think you are very close to the limit on that SUV. I'm not really familiar with the Envoy, but a quick search says it has a towing weight limit of 6000#, so if the trailer's empty, it should pull it.
Does your SUV have a "towing package"? This would consist of a trailer hitch receiver, a 7-blade electrical coupler and probably an extra transmission cooler. You will need a hitch with a 2-5/16" ball. Anything smaller will not stay connected. If your SUV does not have the 7-blade connector, you won't be able to connect the trailer stop, turn and running lights, not to mention the trailer brakes. If the SUV does not have a hitch receiver, you have no way to safely install a towing hitch on your SUV.
How far are you going to be towing the trailer to get it home? Is the trip relatively level, or are you going to be climbing hills? If there are hills, are they serious ones?
If you don't have a WDH, your SUV will be carrying ALL the trailer tongue weight on the rear axle. If your trip is about 10 miles, that's not a serious problem, but if it's several hundred, you're operating in a VERY dangerous condition.
What is the age of the trailer tires? If they are over 5 years old, they are no longer really safe and should be replaced. Again, if the trip is short, you're probably OK, but if it's a longer journey, you risk having one or more trailer tire blowouts during the drive and that can cause serious damage.
Does your SUV have a trailer brake controller? If not, you are going to be trying to stop an additional 5000+# with your SUV's brakes. You will need to drive fairly slowly in this case.
I know my questions are probably not what you want to hear, but you need to be realistic about adding that trailer to your current vehicle.
- Jack