Went well. Thought TREX would be a great choice for a truck that will sit out in the elements. Got a great deal on overstock that was sitting unused outside. Used the dimensions from GMCPaul's site. This is for my LWB 65 C10 Fleetside. The boards were 1"x8"x12'. Took about three hours total for measuring, cutting to length, ripping, and grooving. Boards were cut to length with a circular saw, but all other dimensions were done with a radial arm saw (ripping blade, and a dado blade).
Can't wait to install it!
Wood, non-polished strips/bolts will be a nice upgrade: