Sorry don't exactly know what the TJ stands for. But if my memory serves, it's a wrangler or equivalent? Does it have an I-6 Engine? If you have the I-4 engine, I don’t think it can do it. I don't know what the towing limits on that vehicle would be; it should be in your owner’s manual if you still have it. I would not tow that boat until I am sure it can do the job. Even in 4WD, some ramps are still real steep and you might have an issue getting the boat out of the water if you don't have enough pulling power.
Now for a toad, it would be fine. More knowledgeable jeep owners can also sound off and let you know. I would never just trust blind luck and hope for the best however, so having some hard information would be a great idea. The Jeep dealer in your area should also be able to help you, take the VIN number into the parts office and ask your questions, with that number he should have access to every scrap of info Jeep published.
This is just my two cents worth.
Monty & Janet - 2007 Alpine APEX 40 MDTS
S/N - 75715 - Retired - Master Certified RV Tech