I mounted mine on the drivers side foot well and ran a cable to a plug that I installed on the switch pannel. This way I can disconnect the mic when not in use and keeps it from being stollen.
My MXT500 is mounted above the windshield along with external speaker. Mic clip is on the mounting bar and I have a retractable mic holder on the mirror when using on the trail. The down side of this placement is the cable hangs down in your vision. I tuck the mic cable over the bar when not in use so casual observer can’t tell it’s there. I also have a magnetic antenna mount on the hood witch allows removal. Power is direct to the battery due to the 50 watt power of the radio.