Idea

Our old phone system had the ability to ring our receptionist first and if she was away from her desk it would go to the IVR which I would think would be a standard option for Ringcentral as well but alas, its not. Anyway I was able to create a work-around in Ringcentral and wanted to share my configuration to help others out. Like others have proposed, this method uses a voicemail message for the initial greeting.

1. Create and record your voice prompts and save in the prompts library. I have an intro that says: Thank you for calling company name. If you know your parties extension you may dial it at any time. For the employee directory, press one. For our office hours and location, press two. To hear these options again, press pound. As well as an hours and location prompt, an employee directory prompt, and an after-hours intro prompt. You will also need to create an intro2 prompt that has the same information as intro but says something like: Otherwise stay on the line to leave a message in our general mailbox at the end. IMPORTANT: Leave 5 seconds of silence at the end of this intro2 prompt. As an alternative you could cut the otherwise sentence and have several minutes of silence at the end of the intro2 prompt then most callers wont wait around to hear the beep and leave a message, especially when theyre not prompted to.
2. Next, create your IVR menu. I used the visual IVR editor and created an IVR with a menu prompt with the intro then a branch to employee directory and a branch for hours and location. I gave the employee directory an extension number of 1 and the hours and location an extension of 2. Make sure to set your voice prompts for each under settings for each menu. I also created another IVR with the same options as the first but the intro was changed to the office closed voice prompt.
3. Create a call queue with your receptionist as the only member. Under Call Handling turn on audio while connecting (I used ring tones) and under the member availability and hold times section I set all three sections to 15 seconds. In the after-hours tab change it to connect to extension and select your intro IVR. Under Messages & Notifications I set the message recipient to my call queue extension and changed the voicemail greeting to custom and used intro2 as the voicemail greeting.
4. Under Auto-Receptionist/IVR settings, set your company greeting for both hours and after-hours to bypass greeting to go to extension and use your call queue as that extension.

That should do it. How this works is if the receptionist doesnt answer the phone during business hours the caller gets the voicemail box of the call queue which is your intro2. When a voicemail is playing any extension can be dialed so when they press 1 or 2 it connects to the IVR extensions we created and they can now navigate those menus (this is also the reason for the 5 seconds of silence at the end so they have time to press the extension. After-hours calls will also now get forwarded to the regular IVR intro menu. This also allows for the receptionist to have a voicemail box of their own.

The only downside with this is you need to have a general mailbox voicemail, one you either check or not. The other problem I have discovered is if the caller tries to go back to the root menu after hitting 1 or 2 during business hours it will just replay that extension and not go back. To fix this you would need to give the main menu a one digit extension number and instead of using star to return, you would say to return to the main menu press 3 using 3 as the example extension number.