I just say out of the office. It helps that I have a room that, among other things, functions as an office, but I don’t think that would change my reply. Whether its a real or metaphorical office, you’re still not at work, so it counts.
I used to work with someone who had a message telling people she only checked her email twice a day. You pretty much needed to call her if you needed anything outside of those times. (She worked in a remote office.) I think she had read one of those books on efficiency that recommended scheduled email time. But there were problems with this: 4. My department often had to email attachments or text to illustrate our questions/concerns. And we were on deadlines. Reading a page of text over the phone was not an efficient use of anyone’s time 5. She did outreach & was often out of the office on site visits, trainings, or travel to these places, but never ever set her OOO for these, because she was “working.” However, she was effectively not available to read emails from other staff until after hours on those days.

If you’re feeling stuck, try our free OOO email generator to draft a message that perfectly captures who you are and where you're going. Out-of-Office Messages for Vacation 1. “I’ll email you back once I’ve defrosted.”
One of the only reasons I get voicemails is because our system is set up to send new voicemail messages to your email as an attached file. Now if only it would send the voicemail as a transcript, I’d be set. I don’t mind returning calls, but listening to voicemails is obnoxious, especially because people are really bad at leaving voice messages.