I would look on Amazon for a small LED light that you can mount to the underside and shine sideways. Look for the ones designed for 4X4's. So many to choose from (I looked before). IMO Cheap the better incase they get knocked off. But you might want your mounted higher.
I thought about doing the same thing (Front and rear) but have them shine sideways incase you need to do work/change a tire/set up camp at night.
Let us know what you find. I still light the Idea but I want mine hidden and I would like install each one with its own switch - that way you could use one of them to immuminate a drive / ditch that your going to turn into etc.
2017 Axis / 25.4: Big Foot Levelers, Aims 1200 Watt inverter, Ceramic Window Tint, Full River AGM 6V batteries, Front Hellwig Sway bar / Rear Track Arm, Safe T Plus Steering Stabilizer, PD 4655 converter, Hard Wired Surge Guard, WEboost + WiFi Ranger, LED Headlights/Driving lights, TPMS, Surge tank, Tornado flush, Viair Compressor