Detecting update state programmatically

Is there any way I can programmatically do the following:

- Determine if Automatic Updates has downloaded updates that are ready
to be installed
- Trigger the install of downloaded updates
- Detect if a subsequent reboot is needed?

I need to schedule the installation of the updates around downtimes in
my application and cannot do this based on simple clock settings.

Are there registry entries with this information and an exe I can
call? (Worst case, I can manually set Automatic Updates to auto-
install when I'm ready and switch it back when its done.)

I'd prefer to do this without installing any additional software or
services on each of my computers.

Thanks!