I have a brochure showing coverage for the phone patch system run by the two-way radio / ISP that I work for, with the access numbers on the other side. You just need a VHF radio with a DTMF pad, then there's Zetron gear at the tower. Many sites still in use today because of bad cell coverage here.

I vaguely remember AssaultCube would let you edit the map in real time during a multiplayer game.