OK, So, this may be the craziest question ever. Or maybe not. Here we go:

I have a 91 F150 XLT. The lock on the driver side door will not unlock. On top of that, the inside handle broke off when I tried to open it from the inside. Basically, I have no working handle on the driver side door.

Any suggestions on how one might be able to get the door open so I can get the door panel off and replace the lock and the handle?

 

You should be able to slide a flat screw driver in where the handle should be . Get the screw driver under the mechanism the handle bolts to and lift up on the screw driver.
As far as unlocking the door, I assume you have power locks since it's an xlt.
Or you can undo the bolt with a 10mm socket and install a new handle. I found it to be a pita to reinstall the handle with the door panel in place.
O'reillys has metal handles that look just like the black plastic handles.
I found the pink wire on the switch plug on my 92 was loose. All I had to do is jiggle that wire and it worked again.
If it's not that, then I don't know what to tell you

 

ok. I will give that a try. The whole lock will have to be replaced as the key will not turn in it. The biggest issue was getting the door open.

 

You might think an XLT would have power locks but my '89 F-150 XLT Lariat has both manual locks and manual windows.

When you get the door panel off, disconnect the lock cylinder from the latch and try the key again. It's possible that the latch is bound up.

 

Have you tried pulling up on the lock button? With it being flush to the panel, you'll probably have to use a needle-nose and will probably destroy the plastic cap, but that's a small price to pay.

 

When I bought my truck, my passenger side door lock would not work with the key. I used PB Blaster with the red "hose" in the lock and sprayed quite a bit into it and let it sit. Then I ran the key in and out several times and soaked it down again, and let it sit for 10 minutes. Repeated the key in and out with a little trying to turn back and forth. Then another round of PB and this time black grit started coming out of the lock. Stuck the key in and wiggled back and forth little by little, till the key turned freely. It was just full of road grime and dirt from over the years and now works fine.