There is always the cellphone as a monitor trick. Have one of you leave your cellphone in the room and call it. Leave the other one on speaker and muted. That way you guys can go a little bit away but still be able to hear if he cries.
We had an app on Android when ours was little called "Dormi" that acted just like as baby monitor. That was useful so we could use a Wi-Fi only device and each of us still had our phones on us and (mostly) operational.
Will he be in a pack n play?
A Slumberpod has been the best purchase we've made for travel. It is a pop-up blackout tent that can go over a pack-n-play or travel crib and provides a consistent sleep space no matter where you are. We've done probably 45 nights away from home in almost 3 years and the only time kiddo woke up in the middle of the night was the one night we didn't use the Slumberpod. Highly recommend.
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