Only take 1 or 2 credit cards with chips (backup card in case a vendor card reader won’t read your card). Alert the companies which countries (or other US states) you will be in and when
Make a copy of passport or driver license (photo page) and credit cards (both sides) and keep the copy separate from originals in case you lose them. Make sure you can read the phone number to call in case of theft. If you have the extra passport photo, keep it with the passport copy.
Turn off cell phones when you leave the US. Use electronic devices only when connected to a secured wifi.
Unless you have someone staying at your house, don't advertise on facebook that you are not home.
Remember to get up and walk during the long flights. Drink water, take ear plugs and eye mask.
Pack a change of clothes in your carryon in case checked luggage is delayed
Pack light. Its ok to be seen in the same thing twice. We always wash out clothes and hang up around the room to dry. Or use the laundry facilities. Roll clothes to pack.
Not all countries use the same voltage as the US. Be sure to have enough adapters for all electronic devices. Word of warning, hair dryers need a transformer, not just an adapter or it will burn up.
2 carry on items are allowed per person on major airlines. We usually have back packs and a purse/murse which we could stick into the back pack. Some carriers have weight limits for carry on items, others do not. Delta doesn't have a weight limit, but the size is limited to 45 linear inches.
If train or bus is on your itinerary, read the carry on and checked bag restrictions. Each one is different.
If the flight attendant passes out a customs form on trhe flight out, keep it with your passport - don't lose it on your trip or you will be having a special visit with the local authorities prior to boarding the aircraft home.
If your return to the US is a smaller airport, your entry process will be easier than LA or SF.
Be sure you have a few hours layover as you may need the majority of it to go through customs, claim luggage, immigration, bag security check, recheck bags and find the gate for final flight home. Remember, you will be tired and have no patience. If you make it through the process in less than hour, that's great!
Don't schedule anything when you get back for a few days. Give yourselves a full day after you return home to adjust to the time change. Its the 2nd day when the travel will hit you. Don't go to work, napping is frowned upon.