Very wise to replace the evaporator while you are in there. The cost of the part relative to the labor involved is enough to justify it, evaps can be found for anywhere from $65-190 depending on brand and source.
I'll go ahead and give you a little walkthrough that gets you through it. bear with me if I forget some things, it's been a while since I worked for dodge lol.
Evacuate the AC system, clamp off and remove heater hoses going to the core. remove the 10mm bolt holding the AC lines to the expansion valve on the firewall. Disconnect the battery
Now inside, remove both sides door weatherstripping on the front half, remove the side finisher panels off both sides, remove both A pillar finishers, there are bolts in the oh **** handles then the rest is held by snap clips. remove the screws holding the dash down. pop off the defroster vent on the dash at the windshield. remove all the screws under that vent panel. remove both of the kick panels, and the inner kick panels on either side of the cupholder. remove any screws that look to hold it down. remove the panel underneath the steering column by your knees. remove the metal plate immediately behind it.
Remove the rubber piece on the steering column tilt lever and remove the screws from the steering column finisher. un snap the top and bottom hallves and remove the column finisher. remove all wiring for column, and the linkage for the shifter. remove the bolt from the steering intermediate shaft and slide it off the column. use a bungie cord to keep the steering wheel from rotating. There are 3 or 4 bolts that go vertically into the large metal bracket under the column, remove them and the column comes out, set it aside.
In the door jambs on both sides, looking at where the dash meets the door, there are 2or 3 larger bolts through a piece of metal that goes into the dash. remove those bolts. On the drivers side(cant remember the pass or not) there is also a tab with a metal dowel that sticks into the door frame. bend this tab out til the dowel is out. Now its just a matter of having buddy help you lift both sides at once, and pull out towards the seats. the whole thing comes off as a module. then its time to play find the connectors, remove all the wiring connectors that are restricting movement, and lay the dash on the seats.
You now have the air handling box in sight. the bolts that hold it to the truck are actually studs that poke through the firewall, with nuts that are removed from outside. remove the 4 or 5 of them, and pull the box out. remove all 6 million 8mm screws from the case and split it, change cores, reverse process.
That's going solely off memory of the last one I did, which was an 05 durango. But I remember the durango being mostly the same as the trucks, with some minor differences I omitted like the center console(non existent on trucks) and the solar sensor for auto headlights. Either way that should getcha going in the right direction. Total time for me in a shop with all my stuff and shop air, its about a 6 hour process. In a driveway/garage with a first timer this is maybe a 10hr experience with a friend. Hope this helps.
