Don't Install if You're Traveling
It may be tempting to install the macOS Mojave update right away to test out new features, but if you are traveling for work or pleasure you should hold off.
There are too many things that could go wrong, leaving you without a working computer or without easy access to your backup and reliable internet connections.
If you are on vacation, just wait and upgrade when you get back. If you are traveling for work, don't chance an upgrade that could leave you without access to files and apps you need.
If you are traveling for the holidays and you get a new MacBook as a gift, you should still be OK to install the update since it's a new computer with very little on it.