Taking a vacation with young kids is pretty much just parenting in a new location. They still run the schedule. They will not all of a sudden start sleeping in late, taking leisurely naps and contemplatively reading books on the beach. They don’t really care what you’re “supposed to do” on vacation.
For example, this is what might happen if you go somewhere where there’s a pool:
This is all fine as long as you realize beforehand what you’re getting into. Don’t be surprised if you take the kids to the aquarium and they ignore the fish in favor of running up and down some ramps. They’ll find something to interest them wherever they go, it just might not be what you think they should be interested in.
One tip I do have is to try and stick to a regular routine even though you’re in an unfamiliar place. For example, every day, you might have breakfast, then do an activity, have lunch, nap/relax/play, have dinner, go to sleep. The more you can keep to a regular routine, the better the kids will adjust to the new location.
This idea of a regular routine was reinforced for me recently reading Simplicity Parenting. That book focuses on developing a routine at home, but I’ve found the same applies to being away from home. A regular routine seems to be comforting.