Hyper-V Host, VM and Application upgradation Query

Hi Frenz,

            My organization have an environment,

02 Node Windows 2008 R2 Hyper-V cluster, 15 Vm's (all windows server 2008 R2) are running on the cluster and all the VM's are running SC components (2007 version).

            Activity planned: I suppose to do an up-gradation of all the Host's and VM's to Windows 2012 R2 and finally upgrade the SC components to 2012 R2 UR2 version.

    Query: Kindly someone share your best suggestion/Recommendation/High Level steps /possible ways to do the same. Kindly do let me know for any Questions.