I have a 2001 xlt 4wd. I wrecked it so I bought a 2002 that was 2wd, and put that cab on my 2001 frame. The issue I'm having is figuring out how to install the 4wd selector switch since the 2wd cab didn't have one. Hopefully someone knows what I need to do!

 

Start by examining the 4WD switch you have. There is a bit of contouring on the dash of my '05 (same as yours) but it doesn't look too convoluted.
Gone are the days of threaded tubes which you insert through a hold drilled in the dash with a nut and washer on either side.
I gave my selector **** a tug to see what was beneath but it resisted so I didn't force the plastic on this cold morning.
I'd bet there are 2 screws behind the **** which, when removed, let the switch fall free behind the dash. It might be easily workable.
The selector switch operates nothing but resisters, so there's not much there.
A 3-position toggle switch with a safety cover might be available.

 

Umm, put the radio bezel from the wrecked truck into the new cab....

If it's cracked, find a new one in the wrecking yard or on Ebay.

You won't be able to make the 4x4 switch work in the 4x2 bezel as the posts for the screws aren't molded into the bezel.

 

2 screws right above the heater controls are the only screws holding the radio bezel on, then a couple clips, pull the 2 screws and pull the bezel off.