The Pololu library command reference says in section 8:
Does this mean any pin change interrupt, or only those mentioned? I’d like to use a Ping range finder, which gives a variable length pulse to indicate range, but I’d also like to use the wheel encoders. Am I just misreading that?
All of the pin change interrupts available on the AVR are both listed and used by the libraries. And, as we say in the note, the wheel encoders library conflicts with the pulse measurement library.
It would not be too hard to combine the two libraries for your specific case, but if you are not familiar with interrupts, and if you are not spinning the wheels too fast, you will probably be better off using the pulse library to handle both the encoders and the sensor.
You can read encoders on the SVP without interfering with the PulseIn library. You just have to use SVP-specific functions to read it from the auxiliary processor instead of from I/O pins: pololu.com/docs/0J18/13