The last two posts point out the diachotmy of the issue:
Know your kids - some have LOTS of energy and good dispositions for walking. Others just won't make it, they lack the physical stamina - or are whiners who will make it but make everyone else miserable for the vacation (and vacation may or may not be the time to work on correcting this.) (A lot of DISers start walking with their kids to build up stamina before the trip - which honestly isn't a bad idea just for your kid's health if they are couch potatoish in their nature.)
Know yourself - some people are willing to take their vacation at a pace that allows little legs to keep up (remember, they take twice as many steps as we do). Other people want to commando the park like they always do - regardless of the state of the kids. If you are going to be angry and frustrated because you didn't get everything done due to tired kids - get/bring a stroller (and don't blame them for not being able to maintain YOUR pace). Other people are willing to spend only a few hours a day in the parks, spend their hours in the parks moving slowly, spend a lot of time in the pool or room, and completely miss Expidition Everest because its way over on the wrong side of the park and that's a lot of walking for a little kid - and still leave having had a wonderful vacation.
Know your kids - some have LOTS of energy and good dispositions for walking. Others just won't make it, they lack the physical stamina - or are whiners who will make it but make everyone else miserable for the vacation (and vacation may or may not be the time to work on correcting this.) (A lot of DISers start walking with their kids to build up stamina before the trip - which honestly isn't a bad idea just for your kid's health if they are couch potatoish in their nature.)
Know yourself - some people are willing to take their vacation at a pace that allows little legs to keep up (remember, they take twice as many steps as we do). Other people want to commando the park like they always do - regardless of the state of the kids. If you are going to be angry and frustrated because you didn't get everything done due to tired kids - get/bring a stroller (and don't blame them for not being able to maintain YOUR pace). Other people are willing to spend only a few hours a day in the parks, spend their hours in the parks moving slowly, spend a lot of time in the pool or room, and completely miss Expidition Everest because its way over on the wrong side of the park and that's a lot of walking for a little kid - and still leave having had a wonderful vacation.