When loading your golf cart into the back of a truck is is not wise to use plank wood in place of loading ramps.
While it is true that two 6×6 timbers may be able to handle the weight of a 1000lb EZGO or Club Car plus your own weight planks won’t work. In fact you could hurt or even kill yourself or other by trying the board method.
The guy in the video below shows off what will happen when you try this.
Also most tail gates on trucks are rated at 500lbs max for a very short time. Older cables can break very easily and send you crashing to the ground. It is best to lower your tailgate down out of the way bay removing the cables or by removing the tailgate entirely for loading cart in back.