I ended up biting the bullet and went with Garmin Mobile XT and the new North America 2009 maps. Runs just like the popular Garmin car units and hasn't let me down so far. Although for trips lasting longer than 24 hours, it won't calculate the date of arrival, just the time. For example, I set it to drive from Orlando, FL to Las Vegas, NV and it only displayed the time of arrival -- didn't say anything about which day I was to arrive at that time.
Nonetheless, a great application and one that's still being supported by the company (Unlike TomTom Navigator). I highly recommend Garmin on your WM 6!
https://buy.garmin.com/shop/shop.do?cID=138&pID=11413 (Not a sales link, just product information)