Aero is the least of your problems when hiking 352 miles with your pickup truck.
I recommend going slow, and when you get to the trail head, hide any valuables so nobody will break in. Try to plan to have the fuel tank mostly empty by the time you reach the destination (with plenty to get back to a gas station). I had a full tank of gas siphoned from a rental car when I was in Hawaii hiking the Kalalau trail. I imagine your pickup holds more fuel than the compact car I was driving.