Sorry for the late reply! We had the chance to tow our pop-up with our Jeep this weekend. We had zero issues and barely even noticed that we were towing anything. We went 260 km each way to the camping area and back, so just over 500 km round trip (323 mi for my American friends). We were able to drive 100 kph without issue and didn't go faster than that. I'm sure if we had gone 110 kph or 120 kph (which is speeding) that there would have been some stability issues though.
I think a few things help.
1 - We're super light packers. Everyone always laughs at how simple campers we are. Our gear is small and weighs less than 50 pounds. Many years of car camping and using tents and us being no-frills type of people anyways has led us to being light campers. What little gear we have we loaded to the front to add to the tongue weight.
2 - We don't have an after-market hitch installed to our bumper. Our bumper has a hitch built in. This is the bumper we have:
rear bumper3 - The bumper is installed with this amazing things from a manufacturer here in Toronto (TMR Customs) that are called frame tie-ins. These tie-ins allow for reinforcement of the Jeep's rear cross member and attach directly to the frame rails giving you a rigid and exceptionally strong mounting configuration. They're an absolute must for towing with a Wrangler:
frame tie-ins4 - We had very little elevation on our trip. Southern Ontario is pretty flat.
5 - Our TJ is a manual transmission with the 4 liter inline 6 cylinder engine. The engine is a beast. I think if we went any heavier or longer though it would be a problem because of our wheelbase.
Another interesting thing we discovered is that our fuel economy didn't change at all. Which is awesome. Wrangler TJs are pigs on gas to begin with so it was nice that our fuel economy stayed the same.
THAT SAID, I wouldn't want to constantly be towing with the Jeep. I'm still on the lookout for a replacement vehicle for our Civic that will allow us to tow. We want to be able to bring friends with us too and our Wrangler only fits two people. So the hunt for another vehicle begins!