Our strategy isn't so much tweaked by how many kids are present, as by the total of our entire party- if that makes sense.
With little kids, if you want to do any big rides, then you have to plan on doing rider swap. I think WDW still has rider swap. Rider swap slows down the group a bit, but parts of your group get to ride rides twice. What also helps is if different adults take turns with the baby. (so one person isn't alone with the kids all the time)
Generally, when we go to the parks, our general strategy is to hit nearly everything at least once. So we've always been open to the idea of doing 'kiddie' rides like IaSW. With no kids, we maybe do a few more mountains, with little kids we maybe do a few more easy rides, but basically it is the same.
We do use a stroller, that way the little one can nap. A stroller also means everyone has a place to stow stuff - which can actually be a pain with extended family (everyone wants to shove all their junk in the stroller). But it can also be wonderfully helpful to be able to stow rain jackets and water.
You will need to park the stroller. It helps if one person is in great shape, or you take turns getting the stroller. IT helps if the child is capable of napping in said stroller. It helps to have a rain cover for the stroller.
Another very smart thing to ad to your stroller is something that makes it stand out...like bright colored ribbons on the handle, stickers. you may not want to smother it in fluorescent duct tape, but that's the kind of look that would be very helpful. Otherwise the strollers all look the same.
If we have a stroller, often the little one just naps when they get tired. so truly, it is not the kids who crimp our touring, it's the (out of shape) adults. when the ADULTS get tired (or injure their foot), then a break is a must.
You would do well to exercise before you go. Walk with the stroller as much as possible. Up and down hills is good.
Maybe we are very lucky, but the little kids in our family have always been pretty flexible as far as sleep. If they are well rested when they arrive at WDW, don't have a cold, and get o catch up a little on rest when they get home- then they tend to do fine at WDW with a little more exercise and a little less rest than they get at home. That said, if someone - anyone is not happy- always do something different- maybe take a break, maybe a nap, maybe a swim, maybe get something sweet.
Kids do equal a small shift...less $ on adult beverages, more $ on toys.

(not that we ever drank very much)
As I say, we often go with extended family. No trip is about what any one person wants. We all take turns and compromise. I think that's a great lesson. We are also always flexible.
Along those lines, it is smart to know the location of the little park playgrounds. To a toddler, the little playground near Splash Mtn is just as much fun as any attraction. The monorail is also a big hit. So is the bus for that matter. Know that the post ride area of many attractions have fun things for small kids-like M:S and TT. Many are also fun for the adult too.