First thing I'd check is the drain holes. You can remove the wipers and the plastic cover to get access from the top. Removing the wipers is a bit of a pain, you'll need a thin 2-jaw puller or other wiper remover. You can also pull the fender liner and inspect the rubber grommet at the drain.

When I first checked this, I did not remove the wheel. Just went into Xtra Offroad height and turned the wheel each way to remove the fender liner. From there you can check the rubber grommet or pull it out. I put my finger in there and was a ton of leaves from the previous owner who never cleaned it.

Once that is clear, try your test again. If it's still leaking, you can try to pull the interior panels and headliner but also a bit of work to do this.

 

Here's a short video of the drain plug that gets clogged from the debris that turok mentioned.

 

Here's a short video of the drain plug that gets clogged from the debris that turok mentioned.

WOW that's A LOT of water!! Almost as much water as I had leaves!

That's the grommet to look for, it's about an inch long and the rubber folds kinda into a star shape. Instead of just chopping this shorter, I made vertical slits so they can allow debris to exit a little easier while still having the rubber there to close up a little.

 

You can access it though the wheel well, just pull or cut the drain plug to make it wider. If it's still leaking I'd take an air compressor to the top of the drain by the sunroof and blow it out.