It's pretty easy, took me maybe 3 hours moving with equal parts care and purpose. And constantly losing tools, I have no idea how I manage to lose a drill without leaving where I was seated.How'd you do it?
Marker lights first. I removed the bulb from the light housing, then removed the housing from the fender. The light comes out with a simple twist. The housing has a single nut on the bottom, remove it and you can tip the housing inward and down out of the fender. Reverse for installation. In my case, there was just enough wiring to reach the new mount point, so no electrical was required.
There are two types of fasteners, both with 8mm heads. I used a ratcheting wrench, there wasn't enough space for a socket ratchet.
One is a machine-threaded screw with a fixed washer head that screws into a rivnut. These are located at the tail of the front fender (three, I believe), all three on the small middle section, and on the lead and tail of the rear fender (two at each end, I believe). For these, spray them down with the penetrating oil of your choice - you don't want to pull out any of those rivnuts. You don't have to completely remove the small section (located right behind the front fender) - you can loosen the screws and slide it off once the front fender is removed.
The other is a rough thread screw with a fixed washer head that screws into a plastic block on the inside of the fender. I was generally able to hold the plastic block in place to remove the screw, only needing a pair of pliers once to keep the block from spinning. I pre-thread the new blocks by running the screw through them before installation to make them easier to install.
The rear has the added difficulty of the fender liner. I removed the plastic plug on the inside rear of the fender liner, and just pushed the liner out of the way. It took some doing to get that liner back in proper position. If I did it again, I might look at how to remove the liner entirely to avoid deforming it.
I took the Jeep to a car wash station to clean out where the fender met the body before installing the new fenders. It was pretty dirty there.