Putin is unlikely to be trying to occupy all of Ukraine. The sheer cost of getting bogged down in an insurgency he couldnt possibly win suggests he's going to take an option which plays to his strengths instead.
More likely he will try to cleave off strategically important territory with Russian majorities (forming a land bridge to crimea, maybe all the way to transnistria) and leave Kyiv having extracted a promise to remain unarmed, "neutral" and providing no aid to insurgencies or face another bloody assault.