There are software serial libraries included with PIC 18 C. You would have to use them for SPI or I2C. You might want to look at this app note.
http://kronosrobotics.com/an149/DAN149.shtml or
http://kronosrobotics.com/an149/AAN149.shtml
This would be the coprocessor solution. The coprocesssor could also drive a hobby servo to scan a wider arc or 360 degrees. You would have to decide on the protocol for the master slave communications. With the above link, these micro controllers include coproc functions in the language. You would have to duplicate it on the FRC. The above implementation only receives the first ping to return. I believe the device you are looking at can return multiple echos. Useful for finding things like door ways but adds allot of complexity
Some of the IR devices have a narrower field and can be better for close range.