Following to see what others say as well.
I've been planning on getting the Zoleo messenger as well when I get back on the road this summer.
This past summer I got my ham radio license to give myself another option for emergency communications. ham radio operators have repeaters set up all over the country as well that you might have a chance of hitting where cell phones don't connect. I haven't done enough testing yet myself but I've read about ham operators reaching people 50 miles away, etc, with the right terrain.
Getting your ham license takes a couple weeks of studying, and about $15 to take the test, and your license is good for 10 years.
