So far it looks like they are aiming to take the Eastern part of the Ukraine, including Kiev. Take a look at this speculation from CSIS back in January:I haven’t been able to figure out Russia’s central strategy just yet and I think it’s because we’re still at the generalist stage of the operation where specific objectives haven’t necessarily been acted upon just yet.
Possibly, at this stage, the Russians are just trying to hit as many points as they can to diffuse the concentration of any Ukrainian responses.
However, it does seem that there is a Russian focus on gaining and holding ground outside of Crimea. It will be interesting to see if they try to move both east and west out of Crimea or if they simply move toward the west.
An interesting development in the north is Russia's decision to advance through the irradiated Pripyat marshes from Belarus, as speculated by CSIS.