Well, Bob, I love the fact you are doing this. I dislike the idea that you are doing it alone. Let's face facts: You could be in a spot where pushing a button isn't a good option. So I think "buddy" is the best option. Need a new one? Try Craigslist.
Option #2, some sort of emergency locator beacon. EPIRBS are my top choice. Theyre small, battery-powered beacons that can tell people your position and alert them that you need help. ACR's Terrafix 406 GPS I PLB (Personal Locator Beacon) uses GPS coordinates to tell rescuers, via satellite links, exactly where you are. It will work where cell phones and other gadgets will not. Cost is $400. But think about what it could do for you and your peace of mind!
SPOT's GPS Personal Locator Beacon ($129) uses a proprietary satellite system and subscription service ($99 a year to start). It allows you to send out several kind of messagesjust checking in, for instance. I like it, but the annual fees mount up quickly. The ACR system uses non-proprietary satellite links and is in my view the more reliable and cost-effective device.
That said, no electronic gadget is going to ensure your safety. Try to find a new friend to go with!