Just a quick update...
Over the past few days I've been taking my Echo for a ride, and this is what I have learned:
#1 It connects much better and faster to a dedicated "hot spot" vs the iPhone Personal Hotspot. While trying to connect to the iPhone, I had to switch the iPhone Personal hotspot on/off to restore the connection. No problem with the Verizon JetPack.
#2 It appears when asking Alexa to play a Pandora station, my data usage is within the expected specs or 30-40mb/hr.
#3 My 2015 GMC Sierra has a decent audio system with bluetooth capabilities. As of now, I am using the AUX input as it seams to be providing a more reliable audio connection. (it would be nice to loose this cord, but not a deal breaker).
#4 As of now I'm staying away from the Amazon Music "database" as that one pulls down 2 songs at a time.