My name is James, Ham callsign KH2SR. I have used gotenna mesh with dozens of non hams over many miles of mixed terrain. They are very effective, especially if you setup solar powered relay units on mountains, hill tops and/or tall trees, buildings or other tall structures.
I’ve personally achieved 29.6 mile point to point comms using gotenna mesh with no relay in between while on a mountain top.
I also recommend installing permanent relay units in/on each vehicle. You can either hang them from the rear view mirror or put them inside a waterproof case with solar panel mounted using magnets on top of the car roof.
Gotenna mesh is very easy for non technical users to learn. I highly recommend it.
Check out these other discussions on solar powered relay units as well as modifying them to have high gain external antennas: