Ukrainians mobilizing, but to me it seems just a defensive precaution agains troubly in eastern part of the country, nothing to do with Crimea.
I still believe it would be possible to come to the agreement, if Russians decide Crimea is enough. I mean, Crimea is not really heartland of Ukraine, it has no historical significance to Ukrainians, and to be honest it was integrated in the country with complete bureaucratic bullshit decision. Moreover, even without Russian interference Ukraine would face a great problem with controling the population that wants to be part of Russia.
However, it is part of the Ukraine and it cost Ukraine a lot of money. How come no one comes up with the proposal to organize a fair referendum, this time with international observers and such, and if Crimea decides to split that Ukrainians deliver a bill to Russkies. For example, we invested in Crimea that much billions of dollars since 1954, please pay up. The bill could be 900-1000 billions of dollars. It would be cheaper for Russians than economic sanctions, and Ukrainians wouldn't have to worry about foreign debts anymore.
No one would be too happy, but no one would be too unhappy.
Its not like something like that did not happen before, take Louisiana Purchase for example.