We have to include the children in planning. So we're going to Paris next. We watched some youtube videos of Parisians talking about their favourite things to do, looked at maps and websites and then everyone picked a few things that they'd like to try and do/see.
Dc1 (9) wants the Eiffel tower and the maritime museum and to try snails
Dc2 (almost 6) wants to visit Versailles, try Angelina's hot chocolate and eat pastries
Both of them want the catacombs and Galerie de Paléontologie et d’Anatomie comparée (as do I). We also have to fit in Disneyland.
Then when we arrive, we will have a clear plan of we are doing this, then this, then this etc including when snacks and downtime will be available. Whilst the idea will to be to try new things, I'd rather we compared differences in McDonalds than they didn't eat. Checking menus in advance really helps mine for other restaurents though. It seems to take the pressure off. Also for trying stuff at home before trips, having a sharing plate of new stuff has worked brillantly for us. So plate of individual food that they are comfortable with and then plate or plates in the middle with "new" things for people to help themselves. Dc1 has really expanded what he'll eat this way because it's not on his plate so therefore not stressful.
With the walking, having checked that the shoes fit properly, under no circumstances would we be carrying our 5 year old let alone the older one. Having break stops helps though, we usually do maps in advance using landmarks so they know it's another 5/10 mins etc.
For a lot of major museums, you can download childrens trails in advance or they have specific apps aimed at children. For example I want to go to the Louvre, so I've already shown them some of the art I want to see and why I want to see it. Dc1 in particular needs to understand the plan to feel comfortable, especially when another language is involved. It's also compromise on our part. I could happily spend all day in the Louvre. Dh and the dc less so, so I figure out my must sees in advance and where they are within the museum to save time.
Also fitting in "chill" time is important. We like hotels/campsites with pools for that reason.
But also it's practice I think. We live between two Scottish cities and we regularly do a day in "town". Walking between museums/touristy things and having lunch in different places. That way it's not alien when you remove them further from their comfort zone.
I've never allowed screens in the car (it's either music where we take turns to pick, an audio book, reading or quizzes) so they don't ask. Neither do I allow them at the table. They draw or colour in to decompress.
For us, it's basically removing stressors as much as we can by giving options and choices. Finding playparks, having ice creams and setting clear objectives and time limits. Compromise has been tricky for me too. I'd happily sight see from sun up til sun down but that just doesn't work for us as a family. However mixing museums etc with parks, the pool, snack food options and more formal dining does.