So the plot thickens. It rained last night and no watter got inside the car. I popped the Tonneau cover to see if I could find where the water might be coming in from. No indication that water was leaking into the trunk. However, I noticed something I had not before. There is a channel that runs between the tonneau cover opening and the trunk opening. And this chanel is not sealed and open to water flowing in from the rain. There are two small holes in this chanel on either end for draining this water. Hoses connected to these holes run to the wheelwell and drain the water down under the body of the car in front of the rear tires. My suspicion is that one of those holes got plugged by a leaf or something allowing the water to overflow the channel and leak into the trunk. My driveway is such that the car faces downhill so I am suspecting the water ran down into the cockpit under the passenger side seat. I am going to carefully put this theory to the test with the garden hose and see if I can confirm that is what is happening.