Minimalist method 1.
I have been tring to figure out how to transport a bicycle with another bicycle for some time. I also want to do it with the minimum of special equipment.
Here is what I have come up with.
The transporting bike needs a rear rack. Parts needed: Front axle, "U" clamps, bungie cords and (optional) an old inner tube.
The old inner tube is wrapped around the fork blades to hold things in place while the U-clamps are secured.
The key principle is this: The front axle of the transported bicycle must be secured parallel to the rear axle of the transporting bicycle.
If you can achieve this principle the transported bicycle behaves like a trail-a-bike.