It's a little tricky installing them. I've replaced all the lines on my 98 2 times now (I'll explain why in a moment). My cables, although seized and broken were still in place, so I knew exactly where they needed to be routed. Now I dunno if you know if the weird self adjusting parking brake pedal assembly, but first and formost this needs to be locked in place. After you take off the panel over the brake you'll find a small oval shaped hole in the sheet metal of the brake. You have to pull the cable coming from the front till it stops (I think wrapped mine around a chunk of wood and pulled hard, since the front cable was quite seized). Having a helper would be good. Have your assistant stick a small screw drive/ allen wrench into the hole and it will prevent the brake from retracting. Don't use a drill bit... It'll snap em like twigs, ask me how I know. If your front cable is totally seized then skip this step and we'll handle it later.
I cut the rear cables free, disassembled the drum brakes and freed the ends of the cables in there. Then I spend a few minutes studying the routing, so I could remember when it went back together. Pulled the old ones free and routed in the new ones and reassembled the drums. I reused my intermediate cable and the little connectors. It's tricky getting them apart. Have someone else hold the connectors with a pair of vise-grips (don't squish your connector though!) and tap the barrels free with a punch and hammer.
Now the front...
She's a bitch.
I had to remove the mud flap and flap mounting bracket, then the inner wheel weel splash shield at least half way, so you can see where the cable goes up into the truck. Now get up under your dash and get comfy... Unbolt the brake release handle, now find your bolts holding the brake assembly in place. IIRC there was 3 10mm bolts and they weren't exactly easy to get to. Get those little bastards out and unplug the pedal position sensor connector. At this point your pedal assembly should be loose, and you'll have to lift and rotate to get the cable up and into the cab.
Now if the self adjuster I mentioned was already locked down then you can skip this, but if it is seized then you'll still need to do that, otherwise when you cut the line the adjuster will spin a bunch and lose all it's tension, and it'd be a bitch to get retension it. Now there's some different methods you can use to pull the cable. Grab it with a pair of pliers and twist a couple times was the method I used. All you want to do is get the cable pulled out of the brake pedal assembly enough to get it locked with an allen wrench through the locking hole like I previously mentioned. Once it's locked down, cut the cable and remove it. The front barrel will be a little tricky to fish out.
Now put it all back together. Clip in the new cable and route the cable end into the brake, again this will be tricky... from here just reassmble the same way to took it apart. Connect your cables underneath and pull the lock pin out of the brake and it should suck up the slack and make the line tight. Cross your fingers, you should now have a working parking brake!
Now I'm going to tell you how to avoid doing it twice... and this part is easy. DO NOT BUY AFTERMARKET CABLES! I made the mistake of buying Raybestos cables and they fell apart in matter of less than a month. The retailer and Raybestos both told me to pound sand. I got my Motorcraft replacement cables from Varsityfordparts.com. They have good prices.
Post back up here or PM me if you have any questions, and good luck!