sean: my dumper is at work, but I will try and write something up about how it works. in the mean time, the secret seems to be RA3 it looks. I think it controls if the ROM will dump or not.
you hook power up, an RC, and then reset will return the PC back to the start (I think it actually starts at the very last location in ROM), and I used the clkout pin next to the RC pin to time the dump.
RA4-7 and RB0-7 is where the data comes out. you have to pull test high, also. I just have it wired to 5V by the looks of it when I gave it a quickie look-see friday.
you can just wire it up on a breadboard for testing. that's how I figured it out the first time.