At the moment this is very tricky. FCPX does not behave as we are used to, because there is no reconnect command.
FCPX manage your data in the event. that is your master-controller. BUT it is picky. If you break the link-line or even if you overwrite a file (with same name, duration) then the connection is gone and the EVENT cannot find it.
Now that is bad news and I am sure Apple will have to fix this.
For now my advice is to use FCPX totally:
Move your film files back to their original drive. They should appear now as connected.
Then I suggest to "File->Organize Event Media"
This will create a copy of your clips IN THE EVENT directory. You can now (after the copy is complete) move your original media elsewhere, because FCPX will work with its own copy.
The good thing about this : you already have a backup!
And there are issues when you open files in other programs. So don´t touch the files in this Event directory with another NLES!!! Use the original files instead.
Now you still use all that diskspace on your drive. To free that up you have to "MOVE-EVENT" by dragging it onto another disk to free up CalDigitVR.
I know it sounds weird at first, but I have now made a few projects with it and it is actually quite nice the way this is organized (if the re-connect would work it was perfect). For instance, once you have keyworded your footage you can drag keyword collections to other events on other disks and give those to another editor. he can create projects/timelines and only give you the those back and you then reconnect them with your original event. It is typical APPLE. If you sell out to them they have a nice microcosmos for you, but they like to be incompatible with others.