All good answers but don't go overboard adding wire. Unless you are using really big wire you will loose power to the motors.
Assume 1ohm of cable (round trip out to and back from motor)
That's rather fine wire to get 1 ohm! If you use wire a little bit thicker than the wires going into the motor itself you should be fairly good, and a long way below 1 ohm too.
Rule of thumb: the longer the extension, the thicker the wires.
Oh yes - make it a military job and use tin/lead solder. It's still available - collect some!
Cheers
Roger