Apparently we are not the only people to encounter this struggle.
We found the creators of the Mobile Internet Resource Center, Chris and Cherie. These fellow RVers have shared in the struggle of having reliable internet and they share all the latest and greatest in mobile plans, devices, etc.
It's a wealth of information, and they're always up to date on new gear & plans.
Their video endorsement (mistake #4 at around 6:45)