John,
Max cell range is six miles. It's actually half of that with tower spacing about every 5-6 miles so you are actually doing really well. Not sure how many folks are out your way but calling the carrier with a signal issue is actually a way to get a new tower up in your area.
I live up in the north part of my town and the Verizon signal was 2 bars on a good day. I got all my friends on Verizon to call and complain about the reception in this area and Verizon installed another cell antenna (fake cactus) closer to us. Now, our reception is 3-4 bars and data is quick. The cactus antennae are short -maybe 20 feet tall, so they don't quite have the range an antenna on a power line tower or cell tower would have. It took about a year of complaints to get the new tower in.
I can't see us getting a new tower any time soon unless a mega-farm buys someone out or Honda expands to the east. There is just not the density of consumers out where I live to make it work, and that is why I live out here.
Currently the towers are optimized to give US 33 and the Honda facilities 4G LTE. Once you are within 1/4 mile of their facilities, you pop up to full signal and LTE.
Using OpenSignal last night, I am 7 kilometers from the closest tower or 4.3 miles and the terrain out by me is pretty much flat. I grabbed a loaner T-Mobile phone yesterday from work to test it out and I get 1 bar of service. Still able to make calls, but data use is painful. Lots of buffering. Everyone talks about 5G being the savior for fast data and better call quality but that technology will require even more towers since the signal does not propagate as far as 4G. Ahh the joys of living out in the country.
I think a bit more research in to the different offerings on Boosters and I may try one. If I can get a few more bars, maybe I can dump my satellite internet and go with a hot spot. That will pay for the booster in under 6 months.