To power on a virtual machine from the command line and then open it using remote desktop, thus avoiding having to use the workstation:
(Obviously fix the paths and names for your own machine and it might take a little while before the machine is ready to be accessed.)
cd "C:\Program Files (x86)\VMware\VMware Workstation"
vmrun start "C:\VM Images\MyVirtualMachine.vmx" nogui
mstsc /v:MyVirtualMachine
And to power down:
cd "C:\Program Files (x86)\VMware\VMware Workstation"
vmrun stop "C:\VM Images\MyVirtualMachine.vmx"
Additionally I have seen that if you power the virtual machine off and on again it is possable for its ip address to change. To re-discover it just flush the dns cache before running the power on command:
ipconfig /flushdns