Putin is stubborn and holds the best cards - gas and history - so I suspect Obama&Co will not get far negotiating a deal, any deal. The Crimean govt will soon hold a referendum and the next move depends on that result. If the Crimeans want out of Ukraine - which is certain - the heat will rise and the international community will have to get involved somehow.
Yes, popular uprisings have been fuelled by western ideals plus a bit of underhandedness - now there's a right wing majority in the Ukraine parliament and this will anger Putin.
Russian troops will be 'active' in the Crimea and other parts of Ukraine for the next few weeks/months/years as this situation isn't going to be resolved for a long time.
Ukraine's poor economy is in need of a boost - Russia has given billions, the EU promised peanuts - so something has to happen or chaos will ensue. I get the feeling if the US pump money into the Ukraine this will only harden Putin's resolve. Somewhere along the line a huge compromise will have to be made by one or the other. At the moment it's behind the scenes negotiating and good old rhetoric we're getting.
Where we go from here nobody knows.
I watched Russian soldiers fire above the heads of marching Ukraine soldiers in the Crimea; neither seemed to want to be there! They are like brothers - many Ukrainians have Russian family and vice versa - but a minority of extremists could really stir things up if a stray bullet hits the wrong person at the wrong time. Old hatreds would then surface and who knows what that might lead to?
I hope they can all get around the table. If the US can cut down on aggressive speak, the EU provide some reassurances then Putin might feel he can get something out of it without losing face. Russian stock markets have tumbled - so the quicker they can all agree the better!