Hi Miranda,
I like your idea of adding "Remote" as a new feature to the time off calendar, but until then, suggest you consider having users change add " (Remote)" as a suffix to their last name while they are working remotely for an extended duration (as a visual cue), and/or to create a "Working Remote" Project, with one task per person (per remote stint; albeit with little or no "real work" on the task) so that such tasks at least then appear alongside the other work to which they are scheduled (for context/reminder).
Regards,
Doug