I'm using a number of MCP3208 ADCs to read from remotely-mounted analogue sensors. I'm planning on having a remote PCB which contains the power/ground rails, voltage dividers (where required), multiplexers (where required) and MCP3208s for the array of sensors, with the output signal going to my RPi. The RPi will be mounted approximately 3m away; the cable run shouldn't experience any major electrical interference. I expect sample frequency to be less than 10kHz.
What's the most robust, 'commercial' approach to this situation? Should I stay with SPI, look at adapting the SPI to a differential signal such as RS-485, or look at using a different ADC solution which uses a protocol other than I2C/SPI to begin with?