If we are using our Jeep and our popup camper we have a 10 Meter Ham radio in it that also works on 11 meter (CB) channels we have a much better chance getting out with it.
And we have always carried a Baofeng UV-82 Dual band handheld ham radio that we used while on trips with a local 4X4 club, so I bought one more of them so me and the wife could communicate while I was away from camp and I added a rooftop antenna for on the camper to extend its range. I will do a write up when I install it. I have heard transmissions form Georgia on it while in my front yard here in Montana on it.
I will add a cell phone booster at some point but with those you still need a nearby cell tower, but my ultimate plan is for a dual or quad band ham radio for the most reach.