Solution
The project VIs are stored on the development PC while editing. They can be developed/edited using the LabVIEW Real-Time Module even if the cRIO is not connected to the development PC while editing. The VIs are only deployed during run-time by right-clicking the cRIO target (inside the LabVIEW project) and selecting Deploy.
However, some features will be unavailable while the cRIO is disconnected.
For example, when using C Series modules, if you place DAQmx Physical Channel controls/constants, you cannot discover the currently connected modules/terminals. In this case, you can wait until the cRIO is connected to discover the connected modules/terminals or you can input the required terminal names manually in the controls/constants.