It’s a little bit of a PITA. You have to remove the rear doors then the two rear box sides. Not really hard but more involved then one would think. Make sure to use exactly the right fit Allen (5mm I believe?) or you’ll strip them out as the are tight as hell. Pretty straight forward though
I use a sprayer with a boom that was intended for the back of a 4 Wheeler. I slide it out on the tail gate and set it on a couple 2x12 to span the weight. Its about 1/3 on tailgate and 2/3 in the bed. Some day I will get around to fixing it so it goes up and over the tailgate
The emp rear bumper requires the tailgate to be removed for install. You can google or YouTube it and they’ll give you a step by step. But as @Cuoutdoors said... I’d just figure something else out.