Actually, we've not been told that ET was in the kayak with him when he did the test run (nor how long that 'test run' was--though I'm inclined to agree it was likely pretty short). Only bringing this up as I think another poster also commented on this (previous page). Not to make light of it; just to differentiate between facts we know and don't know.
One fact we do know (from the 20/20 video I just viewed onYoutube), is that she was not pasted to his side 24/7. One clip of him shopping in Walmart shows him repeatedly cycling back to the hair color aisle with his cart; she was not in that video clip. So there is no reason to assume he did his 'test run' with her in the kayak, IMO.
That's why I put "allegedly" in my post because the information that he did a test run came from TC himself; there was no confirmation from anyone else. I also think it is very important to keep our facts straight.
That clip of him shopping the hair color aisle in the Walmart was a from a different Walmart trip that occurred before the abduction.