A tip from Steve Smith (Photos added 6/10/10)

I usually hook our 5th wheeler up by myself. To help me I use a golf ball on a string, I had measured the height that the pin slides into the hitch, I tied a string off to the hitch with the golf ball attached, when the ball is straight up and down I know the trailer will hook up correctly. This way I am not getting in and out of the truck to raise or lower the hitch. Then I just put the string and ball in the opening of the hitch then it is there when I need it the next time. Simple but works for me…