I've ridden my Street Glide into the back of my 4X4 Tundra a few times. The trick is to have the RIGHT ramp. My ramp is 4 feet wide and 9 feet long - plenty wide enough to put your feet down. The ramp also has a slight upward curve in the middle to keep the bike from bottoming out. Backing down is not an issue either. Leave the bike IN 1st GEAR while backing down and let the clutch out to slow you down. Using the front brake is no good because there is not enough weight on the front wheel at that angle.
I rode my Ultra up the ramp into a 27' U-Haul. I had no choice because I was pulling a car on a flatbed trailer. It really wasn't a big deal. Stay on the gas going up, coming down motor was off and I just rode the front brake as I rolled down backwards. The machine made the ride from Chicago to Florida without a scratch. I don't have to winterize her ever again either.
The U-haul truck ramps are about 2 inches wider than the wheels on the U-haul dollies. Not very wide and like you see in the video, if the rider stops part way up the ramp bad things can happen...