I have not been able to get a Verizon 3G/4G device to connect to the AR300-M.
The AR300 will show as connected in the Verizon MiFi 8800L. When I go to the AR300 GUI and select New Connectio and then 3G/4G, select the Location and Carrier it never shows up. It does show up as a repeater but that’s not the function I need.
At least as I look at Verizon Jetpack MiFi 8800L | Verizon it is connected only through wireless, not a low-level connection to a modem. If this is the case, then the built-in LTE-modem capabilities of the AR300 are neither needed, nor applicable.