2003 5.3 engine swap into 99 z-71 help!!!

I was just given a 98 extended cab Z-71 with a bad motor and transfercase.. I have sitting in my garage a complete 5.3/4l60e out of a 2003 gmc 4x4. I have the complete setup computer,wiring, accessories, and all hardware. How hard and what all will I need to do for a complete drivetrain transplant?? Do I have to have a wiring harness made?? I know I have to buy the motor mount adaptor plates, but other than that. I am clueless. any advice will be greatly appreciated!! I have been gone in the service for 12 years and sort of out of the loop as far as my chevy knowledge. lol