When you say your fronts are not working, do you mean that they do not catch much of the mud, or that they are getting caught/rubbed by the tires when turning or something? The devil is in the details they say.
Generally speaking, your conditions are probably muddier and uglier than most US folks are going to see on a regular basis, regrettably, we have relatively little dirt road left....
le' sigh ... and salt contamination is simply a fact of life in the areas that use it (if only people would learn to drive we could probably just use sand, but alas...). Generally speaking, salt comes with water which becomes a spray mist that swirls with the air and hits everything with or without flaps, especially if you like to pass people and that means you drive through their heavy salt mist wake. The best thing for this is regular waxing and a good undercoating, so that when it sits on the surfaces a while (which it inevitably does), it doesn't corrode so quickly.
That said, you might consider some bigger fender flairs. This can not only catch some of the debris and rocks those wide tires are going to throw especially when you're turning the fronts, but they will also give you better cover-up for doing a creative mud flap install in front without it looking tacky. The basic is that you need to get tire clearance from them and low enough to catch the stuff that gets slung off lower. As a rule of thumb, if you can draw a line from where your tire leaves the pavement to the back of your cab, you'd probably like your flap to interfere with that line of "attack" I would recommend you look at some big rig flaps, or like the heavy rubber ones ranchers or big motor homes will run off their back bumper, and then custom cut those to sit where you like, and mount them with appropriate hardware to hold them where they wont get sucked up into the wheels. (sometimes a rearward cable tie off on the inside a a good solution to help allow the flap to flex but not go forward under braking and get sucked up.
BTW are your power steps aftermarket or stock? how well do they work?