I would hesitate pulling a plug from the floor that is under the floor mat, that will put the coax cable in a very dangerous location, causing chaffing and could possibly sever the cable(not to say that under the vehicle is where all of the rain and snow and moisture is during those times of the year, moisture and coax do not mix well at all), and then your radio will not work, also you risk blowing the finals out of the transmitter $$$$$$$$$$$$$$$$$$$ for repairs. you might be able to look at a lip or trunk lid style mount, they simply clamp onto the hood. you can also look at a mounting system that is commercially available that screws to the surface just under the hood and places the antenna mount just outside of the closed hood. or if you wished to put a hole in the roof of your truck you can go with an NMO ( Motorola ) style mount. Properly installed they DO NOT LEAK. and there are also screw on caps that are available so that when / if you do not want to have the antenna installed , you remove it and cover the mount with the cap which protects the contact surfaces from the outside elements preventing corrosion. as for running the cable into the cab. If you look under the dash on the drivers side there are several penetrations through the fire wall that are OEM. find one that has only wiring or, say a control cable passing through it. Use a razor knife and cut a small slice into the boot away from the OEM component and pass the coax through that small opening and then re-seal it with silicone. then route the cable under the dash and to your radio keeping the now accessory wiring ( coax, and power leads) tied neatly with nylon cable ties. you can tie these new wires to the existing OEM wiring under the dash with no issues. remember not to tie wiring to metal components, and use the proper sized fuse on the 12v + lead going to the radio. good luck