From what I understand on a 2000 TJ is that the MOPAR part was discontinued -> MOPAR 82205621AB. When searching the web I was able to locate this part in stock at this authorized Chrysler parts website:
https://www.moparpartsoverstock.com/p/__/WIRING-PACKAGE-Enclosure/6864387/82205621AB.html.
You're right about it being more difficult than some would assume. Its hard to judge by instructions whether someone is capable or not of the installation, certainly one to this extent and I would definitely give it a try if I needed to install it.
Here are the instructions I was able to locate for her TJ's model year and hardtop wiring kit installation instructions which should for the part number listed above even though its not explicitly stated in the pdf:
http://www.morris4x4center.com/pdf/82207078.pdf.
I can't guarantee the seller or the instructions provided are too accurate to any extent without confirming it with someone who has installed it on that particular TJ. I can only do so by verifying the installation instructions
and the MOPAR number/kit with someone from Chrysler to ensure the project would have all the tools and documentation to properly undertake.