I think we are all missing something here, he said he would need 60 meters of wire to wire up 6 switches to the arduino. To my mind that means the switches are not 60meters away but 60/6 = 10 meters away. I suppose he forgot the earth return otherwise that would make it 5 meters away.
With a common earth return (sorry ground), at 10 meters a good pull up resistor of say 680R at the Arduino end should see the problem cracked.
Yes you will need 6 inputs or a port expander if you want to sense each individual switch.