Actually, you can manually enter a static location and have the radio transmit that without having a GPSr connected.
I bought my THD7 at Hamvention and use is with the Magellan Sportrac Map. Works great!
I made a cable from instructions I found in the internet via google.com. The instructions in the user manual are misleading. If your cable does not work, try reversing the send/receive pair and give that a shot.
You can also buy a cable on ebay for $10 or so that is custom made to your GPSr.
The free programming software from kenwood makes setting up for APRS as well as general operation a snap.
I highly recommend this radio to anyone interested in getting started in APRS.