You should be good to go.... 100k means nothing if it was maintained well. The install is just as you said, straight forward. I opted to remove the case from the Jeep... others leave it in place.
Just follow the instructions.
Lockring pliers are a MUST ( not snapring )
10mm 12 point socket for ONE BOLT is a must on the t-case
Here are some pointers for you.... read post #12 AND #19 BEFORE you star