it was amazing where I would pickup signals in remote areas, particularly when texting messages...packets don't need much signal continuity.
^^^

The cell coverage map layers on Gaia Maps can help me find reliable cell coverage. But I augment my Verizon voice and txt with VHF amateur radio. I can almost always send texts through the global APRS (
Automatic Packet Reporting System) to Mrs Brian letting her know my status when out of cell coverage. The system uses GPS in the radio to send my coordinates when it transmits with a link in the text to a map showing a Jeep - SUV symbol labeled with my call sign. The APRS tracks all transmissions and I have the radio set to "beacon" every 5 minutes when I'm
actually driving while fishing-hiking-camping so she can look at the link in the text, or use a browser bookmark at any time to see my route and latest position.
So far the only area I've been with poor to no cell
or APRS digipeater-Igate coverage is a relatively small area east of Chinook Pass on 410 from Lodgepole below Fife's Ridge down to around Nile. However VHF can have "ground wave propagation" (reflect off the ground), and has around 100 miles of LOS radio range with 50 watts, so if I drive any distance on forest roads up above 410 I can connect through the Bethel, Shriner Peak, or Crystal Mountain APRS digipeaters. Our home VHF base station
could connect to my mobile through IRLP (
Internet Relay Link Project) repeaters but it's a rather complicated process. As a side note, I've been able to talk to a friend in Korea through amateur IRLP repeaters but cell is much easier with an international calling plan. Our base is not set up with APRS for her to respond with messaging directly to my mobile but as
@krusty mentioned cell texts can work in the hinterland for non-urgent comms.