I'm not sure how much time you spend out in the landscape, so I don't know if a satellite phone rental would be more cost effective. My wife and I camp in Death Valley on the occasional Thanksgiving, and we rent a satellite phone for the week we'll be out there.

Overhead canopy definitely affects reception, but that's not a problem for us in Death Valley. You'd have to know how far an opening is that the phone can see a satellite through.

We take local numbers for hospitals, ambulance, and tow trucks, as well as our Triple-A number. The nice thing about a sat phone is that you know you've gotten through and talked to someone who can help, they can stay on the line and give instructions, if need be, etc.

If you do a search for satellite phone on Google, you'll get lots of rental places, as well as places that sell them. GlobalStar has a system that appears to be failing as a result of radiation damage to the satellites. Iridium is still working. Both systems cover the US and the Caribbean.

Rentals vary all over the place in prices. Some include free shipping, some charge exorbitant amounts going and coming, but cheap rent. I always run the numbers for all the charges to see which is least expensive overall.

If you have a chance, try a rental your next landscape trip and see how it works for you, especially if you're going to be under the canopy. I'm a very happy camper in the boonies with a sat phone. Like you we haven't needed it for real emergencies, but we've helped fellow campers who've broken down and we've gotten weather reports for the Sierra Nevadas to check whether we want to come back via Reno or Barstow. Sat phones come in handy even when it's not life or death.