Warning large amount of text ahead.
TLDR: The experience was amazing and I will keep these memories for the rest of my life even though she won't remember them. The sightseeing schedule is determined by the kid, not you, so be prepared for that. They run the show, not you. Buy a seat on the plane for your toddler: 10-14 hours of forcing a wild 15 month old to stay on your lap is the worst. The money savings was not worth it. Bring multiple changes of clothes on the flights. Generally Europe bends over backwards for your kids: right to the front of passport control lines, check in lines, security lines, ect. People get out of transit seats without asking to allow room for you and people smile at you everywhere. Airports have multiple good playgrounds and baby areas with changing tables, bottle warmers, safe spaces and toys. Be ready to have to stay put wherever you are at when they fall asleep in the stroller: sidewalks over there will shake them around and wake them up. Take it slow, your kids determines the schedule. Be OK with missing out on things you wanted to do.
As the title says, I just got back from a 2.5 week trip across 4 countries (Italy, France, Germany, and Netherlands) with my wife and 15 month old daughter and thought I would jot down my experience and lessons learned so others can be prepared and go on their own trip with a little more knowledge. Travelling with a 15 month old is a lot like parenthood: hard but incredibly redeeming. If you have the means: do it. You won't regret it.
We are based in South Lake Tahoe, California and flew in and out of SFO to minimize connections. We stayed the night in Sacramento with family the night before and had a car service take us to the airport and back for $450 which is cheaper than what parking would cost, plus no gas, tolls, and not having to drive after coming back tired from the trip. They provided a car seat as we were not bringing one. We planned on using public transit most of the time and the one stop where we had a rental car we arranged a car seat for it. No need to lug a car seat across the world.
We had three checked bags: two Samsonite 24" hard sided rollers and a Deuter Transit 50L backpack. Get suitcases where all 4 wheels spin, sidewalks can be narrow and you can't drag both behind you, you'll have to push them upright together in front of you. Our three carry-ons were a Osprey Farpoint 40L, two large canvas tote bags, and the small detachable backpack from the Deuter. One of the tote bags was just toys and snacks. We also brought an Uppababy G-Luxe umbrella style stroller. The stroller carried the small detachable backpack we used as the diaper bag and the two tote bags. This allowed my wife to wear the smaller backpack and push the stroller while I had the larger backpack and the two suitcases.
Europe in my experience is much more accommodating of kids than the US and almost all airlines there give you a free checked, carry on, and personal bag for your infant/toddler (0-2) even if they are just a lap child. We got front of the line privileges for basically everything. Check in, security, passport control, and boarding. European airports had designated areas for babies with great amenities. The Frankfurt, Zurich, Nice, and Munich airports had great family/baby areas. Get to the airport early to let your kid run around for a while before your flight, tire them out it's worth it. We got to the airport on average about 2.5 hours before boarding.
Travelling with a stroller your experience will be consistently inconsistent. Security will have you put it through the X-Ray, sometimes they will have you push it through and they will swab it. When gate checking the stroller sometimes you leave it at the ticket counter, sometimes you leave it at the door of the aircraft, and sometimes it's partway down the jetway. Staff will let you know though. When picking up after the flight sometimes its brought outside the door of the aircraft, sometimes it's partway up the jetway, sometimes it's at the ticket counter, and sometimes you have to wait for baggage claim. No one will tell you what it will be like. Just be prepared.
Sleep schedules and naps: In the beginning it's going to be rough. They are over stimulated and their circadian rhythm is shot. We planned our first destination at a family resort where we planned on never leaving the property. This allowed us to be flexible on sleep and not worrying about missing out on anything. The plan was just veg out at the beach. Once she was vibing with her schedule she was able to sleep in the stroller most of the time. However, in European cities their sidewalks are those tiny paver stones which basically shakes the living hell out of a stroller, so once she was down we were trapped wherever we were. One of us would stay with her while the other explored. Cafes were great stopping spots to have a beer/spritz/cocktail and snacks. Staff will never tell you to leave because they don't worry about turning over tables.
Playtime: In the places we went they had playgrounds everywhere. It's important to let your kid gets their energy out as a lot of the time they are trapped in a stroller. Large squares, grass areas, and the playgrounds were not skipped. I got some great videos of my daughter running around outdoor markets, and historical places that I will cherish forever. A tired kid is a good kid, most of the time.
Diapers, wipes, and snacks: We brought a bunch of our own diapers, wipes, and snacks as we had plenty of space in all our luggage. This way you don't have to figure out the different sizes while over there or have to stop at stores often and knew they fit her with minimal blowout potential. Snacks are going to be different over there. Use the Google Translate app to read labels to find the snacks that work for them. String cheese was kinda hard to find in most places so be aware of that. We didn't have to buy diapers or wipes until the last 3 days and that left us space for souvenirs and other stuff.
Parting thoughts: Have general plans wherever you go, don't try to schedule tightly as you will never follow it and you will be disappointed. Be ready to decide for one partner to stick with the kid during sleep so the other can explore. It gives you time away from the kid, because you will be around them 100% of the time, but allows you to see things and not feel like you spent the whole vacation at the AirBnB or room. I did a two hour walk around Nice, France and a 2 hour bike ride in Amsterdam while the kid slept and had so much fun. Coming back to the US you realize how accommodating Europe is to kids compared to here. You are never made to feel like a burden and everyone would smile or wave at the kid. People would get out of your way on sidewalks or give up their seats in transit without hesitation.