Neil MacFarquhar has the straight skinny for you on how Vlad planned out the conquest of Crimea at least two weeks before the referendum that sealed the deal.
It's in the New York Times, so it's obviously true...
What it is, is an obvious piece of non-news.
The Russian military would have gamed the occupation of Crimea routinely and regularly ever since 1991. That's when the usurpation of the Crimean peninsula became a serious possibility. It would have amounted to serious negligence if Russian security gaming had NOT planned for the need to block NATO designs on Crimea.
It's fair to say that Russia has been harbouring contingency plans re: Crimea since 1991, not since two weeks before the referendum in 2014.
NATO designs on Crimea were always a foregone conclusion. After all, that would deprive the "evil empire" of its only warm water military base. What a prize that would be for the NATO warmongers!
It's safe to say that the Russian military had contingency plans to preserve its Black Sea assets even in the Yeltsin era.
When the Maidan putsch came to fruition, Putin realized he had to act. Contrary to what the NYT would have you believe, the plan to repatriate Crimea wasn't hatched two weeks before the referendum; the plan was over twenty years old.