We're full time RVers. I did extensive research for how to get internet on the road on a budget prior to hitting the road
I found the best resource for information is the You Tube channel Mobile Internet Resource Center.
We use our cell phone data, exclusively, for internet. Our carrier is Visible, which is a subsidiary of Verizon. The cost is $40.00 a month for truly unlimited everything and includes hot spot for one device. We joined a party pay group (search Visible Party Pay on Reddit) which dropped our monthly bill to $25/mo. There, truly, are no data caps and I think we use around 30 gigs a month between Netflix, YouTube and general net surfing. We also have a cheap AT & T plan through Cricket Wireless as a second backup, but so far, the Visible plan is far superior. We've been using this set-up for four months and have no complaints.
As far as coverage, we mostly stay on the west side of the US. With all of the new towers going up, and Verizon vying to hold the top place in coverage, we rarely have trouble getting service, but there are camping apps (ie. Free roam) that are a great resource for finding coverage in remote areas.
I'd be happy to answer any other questions that you might have.
One more thing to add. When we lived in a sticks and bricks, our monthly internet bill was just under $100/mo and it wasn't uncommon for our service to go down. I much prefer reliable internet we have now and only pay $25.00/mo.