Where can I download just the IPE for windows 10?  Or do I have to get like 10 gig of other stuff just to have it?

You can check how many things you can exclude from the 10 gig download when you run the installation.
You might be able to exclude mplabx and only include IPE

https://www.microchip.com/mplab/mplab-x-ide installer here @ 1GB its a common installer for IDE/ IPE
While installing you can uncheck IDE and other device architecture which you don't need.
 

Be careful which devices you exclude. The IPE will fail as it expects certain devices to be present at start up.
 
It will not allow you to re-run the installer and install what you need. You will need to uninstall and start again or install it in a non-default location and run from there.
 
The installer was designed by idiots.
 
Have fun using it. The UI was designed by more idiots.