My suggestion is to use Cat cables. The Ethernet cables work very well for long distances. You have 4 twisted pairs in one cable. 50 ft is no problem.
To reduce noise you need a much smaller capacitor. This is the way I have connected the pins. The capacitor to ground is 10nF, the series resistor to damp the noise is 1k.
The current going to the switch is just 1mA with the 10k resistor. If you are using the internal 50k resistor you could drop the series resistor to 200 ohms. The capacitor could also be a bit smaller in this case.
I even have a photo of my DiscoCap board http://discohat.com/discocap/
But the most important thing is the software. Read the switch value a few times before accepting a change. I read it 3 times during 150ms. If all 3 readings are the same I believe in the state of the switch.