To answer the OP's question, it is a LOT of work.
My windshield needed to come out to fix my driver side fender properly but if the top section of yours is okay, it can be cut just above the body line and you can leave the windshield frame intact. I needed a new windshield anyway...
Get yourself a good spot weld cutter set, like the
Blair 11096. Use cutting oil and go slow, don't cut them dry or spin the drill too fast. Toward the end it was getting a little dull, but I used a single blade to remove all the spot welds from my van's fenders and the donor fenders.
Good luck!