We use WeBoost in our RV and in the vehicle while on the road. To the OP, if you see vehicles going down the road with a weird looking antenna with a big oblong blob on top of it attached to a mirror, etc, its the long range WeBoost antenna. Lots of truckers and fleet users are using this now. We typically use the magnetic small antenna that attaches to the roof with a cable running through the door seal as the major highways around the country rarely have bad service. This system just boosts cell signals. It's not carrier specific so if you use verizon, AT&T, Sprint or whatever it boosts their signal.Good boosters aren't cheap. Avoid the cheap junk on Amazon and eBay. They cause more problems than they are worth. Make sure you follow the directions and get the antennas sperated. https://www.weboost.com/ makes good products that support most carriers.
We bought the system that has the kit for the car and for the RV. The RV model has the long range antenna externally as well as the long range transmitter inside. I can sit in the living area while the wife watches stuff on her ipad in the bedroom.
The RV park we stay at in Colorado has almost zero cell service. Most folks have to drive to town to get some signal to make a call, etc. We don't have to do that.
The cabin we stay at in New Mexico to elk hunt has zero cell service inside. There is one little spot in the driveway where one can stand to make a phone call. At -10 to -20 degrees below zero, the conversations don't take long. I took the WeBoost to the cabin and we all got cell service inside. It wasn't the best as its only a cell amplifier. If the signal is terribly weak, it can only do so much.