Divide the country like Czechoslovakia in 1993.
This makes quite a bit of sense.
The Crimea has a population of little over 2 million, and trying to hang onto it will bring Ukraine nothing but headaches. Of course, they would be abandoning the non-ethnic Russians -- and especially the Tatars who got their belly full of Russian treatment during Stalin's reign -- to their fates in a country that has shut down the free press, that is nursing xenophobia and hate-mongering as state policy, and that is in the throes of almost insuperable demographic and social problems.
But Ukraine, which has neither the economic nor military force to take on a Russia willing to play hardball, has a real chance of becoming a prosperous, progressive nation if it can align itself with western Europe. If the price of that is losing the Crimean, then so be it. A strong, stable, and democratic Ukraine without the Crimea is a much better deal (as least for those fortunate enough to live outside the Crimea) than an unstable, harried country trying to hang onto a region for misguided reasons of trying to protect an ethnic Ukrainian minority in the Crimea.
That may sound a bit cynical, but if we haven't learned by now the lessens almost two hundred years of Balkan history and pan-Slavism taught us about trying to build government policy around ethnic concerns, then there is really no hope for us.