I struggled to get APRS working with my Kenwood TH-D7A/G. The following things were done. I haven't confirmed all of them were necessary...

• On the GPS... (Magellan Meridian GPS)
• Set speed to 4800Bps from GPS to radio.
• On the Radio...
• Made sure that GPS was sending information to the radio by using the POS button
• Made sure that the radio was set for waypoints to be "....MGN" to work with the Magellan Meridian GPS I am borrowing.
• Set Band A freqency to 144.390
• Set Band A as the data band
• Set Band A offset to "0.00" (default was .600)
• Set CTCSS tone to ON for Band A (This is to squelch all the "modem" noise.)
• Set My Callsign
• Set My Icon
• Set Data TX as AUTO
• Set TX Interval to 2min
• Set POS LIMIT to 150mi (help eliminate information I don't care about)
• *IMPORTANT* Set Packet Path
  From: RELAY,WIDE
  To: WIDE1-1,WIDE2-1
• Pressed TNC so that ONLY TNC appeared (No "packet").
• Last but not least... pressed the "BCON" button.