Thanks, John. I'll certainly report back with my results. I may go on a training run up to the 7.8 point, so I can at least see how it works till there. It's really a great feature for having family/spectators follow you along the route. I used it for the GOG this past weekend and it worked perfectly. The only glitch I have found (and have contacted Garmin about it) is that there is apparently a limit to the number of individuals you can send the link to. I tried to send it to about 30 people during the Boston marathon this year and, much to my chagrin, got an "could not send" error message right as I started the race.
In response to:
I have not used LiveTrack, but I know that Verizon service is spotty along Barr Trail.
We use their cards for the timing gear. Some locations are ok. Others like Barr Camp require an external antenna placed in a certain location. Above treeline I've had fewer issues with voice calls but the data service may or may not work as you are on the edge of what it can deal with. Once at the summit, the second you step away from the east face the signal is usually lost.
Either way, we expect a full report on Aug 18th. :-)