An automatic reply should answer a simple question: when can the sender expect to hear from you? It rarely needs a hotel name, a travel route or an explanation of who is at home. A short, realistic message is easier to keep accurate.
Choose the last day carefully
In Gmail on a computer, open Settings → See all settings → General and find Vacation responder. Set the dates, subject and message, then save the changes. You can limit replies to people in your contacts; check the actual options in your account.
Google says the responder runs from 00:00 on the start date through 23:59 on the end date unless you stop it sooner. If you return on 8 October and want replies to stop before that morning, selecting 8 October as the last day would keep it running too long. Review the date range against your real availability.
A sample message might say: “I will start reviewing messages on 8 October. Replies may take longer than usual.” That promises less than answering the entire inbox immediately. Check the signature too: Gmail adds it below the automatic reply.
Test without expecting a reply to every message
Use an appropriate account to send a harmless test, respecting any contacts-only restriction. Gmail normally replies once to a sender; another reply can follow after four days or after you edit the message. Spam and subscribed mailing-list messages do not receive it.
On your return, confirm the responder is off. Any separate calendar availability setting needs its own check; do not assume this email setting changed it.