I hate to post something that is actually somewhat serious, but I was always taught the Rapture happens at the beginning of the Tribulation and that was one of those things that happens during the Tribulation. Anyway, that was how it was always presented to me. There is nothing left that is required to be done prior to the Rapture occurring.
Thinking of South Park, are all the Mormons still here?
There are several competing theories about when the rapture occurs. Let's assume pre-trib because that's the hardest to predict. The temple is desolated in the middle of the 7 years of Great Tribulation. I think it will take more than 3 1/2 years to build the temple and get it ready for dedication. (I have no scriptural basis for this but I think the Antichrist will desecrate the temple
at its dedication; neither he nor G-d would want sacrifices to resume)
I'm studying the book of Daniel right now; just getting to chapter 9 (the 70 weeks)
What about the SP Mormons? :)