Riding it up the ramp?
That's crazy if you ask me. If you ever have any problem, your feet are now several feet from the ground. No thanks.
I just purchased the easiest solution: a tri-fold ramp at Sam's Club. The ramp was $87.04 and is about 45" wide and 77" long. You strap it to the bumper with one of your tie downs and it can't slide away from the truck and dump you on your head. Then you can walk a bike up the ramp or even ride it up and still have a place to put your feet if something goes wrong. It will also work for an ATV in the back of a truck. It beats a 2x8" by a longshot. Yeah, it was more money than a 2x8, but dropping your bike once off of that 2x8 will more than cover the purchase price. Because I don't know about you, but when I drop my bike like that, I seem to damage expensive things like pipes, radiators, and the like. Or maybe just a clutch lever, but only when I don't have a spare on hand.