>> I want to be able to use my edited files in InDesign but the only way

>> I know how to do it is to export them to a folder in the finder.

That is the only way, yes.

>This poses a couple of problems. For one it doubles the amount of disk

space I use

>> and perhaps more importantly it will not bring the changes I make in

>> Lightroom over to InDesign.

  Of course it does. Why would you think it doesn't? You export as a TIF,

  with all the edited changes applied to it. Then use the TIF in InDesign.

>> Does anyone know where Lightroom saves the edited files after they

>> have been edited in Lightroom?

  You misunderstand how LR works. There are no "edited" files. All there

  are are your original files, and a set of edits (stored in the catalog).

  So the file you see in LR, with the editing changes applied to it, does

  not exist as a separate file anywhere. It only becomes a separate

file when you export it.

I don't know InDesign, so your mileage may possibly vary, but I don't get involved in formal LR exports and imports when editing with other apps.  What I do when I need to use another editing app in addition to LR is right-click the image in LR and select Edit In... and pick the app I want to use.*

I'm given three choices for the other app:  Edit a Copy With Lightroom Adjustments (the choice you want in your example), Edit Copy (start over, ignoring what I've done in Lightroom), Edit Original (ditto, but BZZT! not a great idea, to me at least).

The file opens in the other app (and also in Lightroom, as a copy) in the default file format that app is set to use, such as .tif, assumed here.  I make the edits I want there, and then I Save the image again within that app.  That saves the app-edited .tif copy back to the Windows folder being used by Lightroom for the imported .dng Lightroom image files. Note also that there is now a second copy of the image that appears in the Lightroom filmstrip, adjacent to the right side of the .dng image, that is the .tif file and reflects all the edits in the other app. I can make further edits within Lightroom to the .tif (or to the .dng file without the app edits), but in the .tif file, I now can't undo any changes made before I saved in the other app.  Those edits, including the Lightroom edits before opening in the other app, have now become destructive edits in that .tif file.  (This is why I recommend working with a copy, not the original.)  If I need to undo something LR did before I went to the other app, I delete the .tif file and start over with the .dng.

When I'm done editing from LR (I let LR manage the final edited copy), I can Export that .tif file with any additional edits LR made, Print from within LR, etc.

*If you can't see the app you want to use when you select Edit In, go in LR to Edit>Preferences>External Editing tab, and under Additional External Editor, click the Choose button and navigate to the .exe file for the app you want to use.  You also set the file format and other preferences there. Save your new preference with the OK button, and right-clicking will bring the other app up in LR as an Edit In option.