Towing with a TJ is not a problem, as long as you take the time to set it up right.
Try and find a trailer with electric or electric over hydraulic brakes. Trailers with surge brakes can usually be converted to electric over hydraulic. You’ll need a trailer brake controller for the jeep. A breakaway kit is not legally required in some states but a very good idea from a safety and liability perspective.
Make sure you set up the tongue weight and coupling as accurately as possible. Tongue weight is usually 10% for large trailers, and sometimes 15% for smaller trailers. Buy a tongue weight scale if you’re unsure.
There are three kinds of couplings commonly used on TJs. The most common is the standard ball coupling. This is fine for on-road and gravel road use. Some off-road enthusiasts will convert to a three axis off-road coupling for better articulation. A few also use a pintle hitch and lunette ring for positive engagement. Any of these are fine used properly.
You’ll want safety chains that match or exceed the capacity of the trailer. If you don’t have any, 1/4” Grade 70 chain with a couple of 1/4” Grade 70 clevis latch hooks will work for anything you tow, including flat towing the jeep itself.
To maximize trailer stability on the highway, you’ll want the coupling as close to the rear axle of the jeep as possible. Meaning no hitch extensions. In some cases, it may be preferred to chop and redrill a ball mount to get it closer to the bumper. On the trailer itself, longer tongue length will maximize stability. (For off-road mobility, the opposite is preferred. Hence why many off-road trailers have adjustable tongue lengths.) A rise or drop hitch may be needed to keep the trailer level.
Sway control bars are optional but do have a small but measurable effect on trailer stability.
Trailer parking brakes are a good idea if you plan to decouple the trailer and set up on potentially sloped areas. They’re not intended to replace wheel chocks, but instead be a supplement and emergency backup. These can be retrofitted to most electric drum brakes.
If you start noticing control issues with the trailer, there are a few things you can also do to the jeep to improve towing stability. A stiff sway bar like the Swayloc in the front and maybe even a Hellwig in the rear will significantly stiffen roll capacity. Airbags in the rear will reduce bouncing as and eliminate squat. Airbags in the front will reduce movement to a smaller degree. Adjustable damping shocks like the Fox adjustable CD shocks or the RS9000XL can also be used to adjust the springiness of the ride. Running the tires a few PSI higher than normal (not exceeding sidewall pressure) will also help to a small degree.
As for trailer wiring, there are several plug-in kits that work with a 4-flat. If you intend to tow frequently, converting to a 7-way RV plug is preferred, as it will also allow connections for the trailer brake controller, trailer charge circuit, and reverse lights, in addition to turn/brake, running lights, and ground. Be sure to use a minimum size of 10AWG for charge and ground. I recommend a relay or contractor to isolate the charge circuit in the TJ when the engine isn’t running so you don’t simultaneously kill both batteries by accident.
