Long programming cable

What would be the easiest/best solution for a longish (50-ft) programming cable for an RCM4310 module? 1) Use the supplied serial-USB cable, and then run an extended range USB cable connection, or 2) Make a 50-ft serial cable that plugs into the RCM4310, and use a serial-USB converter at the far end? In the latter case, can the serial cable be a simple 3-wire RS232, or does it need more wires?