The long piece that is located in front of the rear tire is held on by a few screws and a strip of padded adhesive. The mud flap behind the front tire is held on by a few screws, pop rivets, and padded adhesive.
Removing the front mud flap removes part of the side cladding and fender flare, which doesn't look too good.
Another option would be to cut the front mud flap along the line of the body. Then remove the long strip between the front and rear tires. Get some custom rock sliders made to protect your rig from those nasty boulders and You are good to go. The sliders should cover the area from which you removed/cut the cladding.
Check out this link, someone did something similar. http://motorcare.com.au/demonstrator2.htm