Verified answer

You may not have a choice.

Not easy, but route it down the back under the chassis and up into the engine compartment. From there take it through the firewall at one of the existing access points. Make sure you secure the wires so they won't swing loose, drag or get into something and you may have to put a longer coaxial cable on then comes with most Mag Mounts. If you do it carefully you can go through the outside of the doors. I run three mag mounts on my company Expedition truck, all going through the door where the rubber gaskets are.

my suggestion would be to just drill a hole & get a roof mount.

either a Wilson 5000, or a K40 roof mount

(ps 2 of the best antennas made - wilson is better than k40)