No drilling needed, just run the coax down the back of the cab and tie it off with zip ties where you can to keep it secure. Run it down between the cab and bed, then once under the truck you can run it forward under the body and up to the firewall. Secure it in place with zip ties as you go, keeping the coax away from any existing electrical wires. There should be an unused rubber grommet in the firewall to poke a hole through for the coax cable, or you can cut a small hole in an existing grommet and pass it through to the inside of the cab that way. However, you still want to try to keep the coax cable run as short as possible.