I meant to post this earlier but forgot. I bought a SPOT satellite tracker before leaving Calgary and have been testing it during my trip.
If anyone is interested, you can follow my progress here (there are currently 13 pages):
SPOT Shared Page
I'm very impressed with the SPOT. Besides the tracking mode, there are three buttons for sending text messages to family and friends. You set up the text of the messages online in advance. So on this trip, I send an "I'm here" message to my family at the end of the day. I had a message yesterday from my daughter who said "Dad, I see you are travelling down the Colorado River. I hope that is on a raft and not in your car."
There is also a guarded SOS switch which will send a position to the appropriate SAR authority.