We’re biased because we LOVE DLR in this house but I feel like it’s compactness (meaning its walkability) + more chill vibe make it a lot easier to do relaxed touring like is sometimes warranted with kids & reluctant DH’s in tow. It’s much easier to send them off to the hotel for R&R when it’s adjacent to the parks.
If your DD is at ALL princess inclined & you have the budget for it, Napa Rose brunch with the princesses is AN EXPERIENCE. Each of the 5 princesses we met was the best princess interaction we’d had with that princess & all the food they bring to you for the apps portion & dessert portion was adorable (& all good & tasty too). The buffet was the only part that wasn’t a homerun hit, but we did do the brunch on the tail-end and part of that may have been that the buffet was wrapping up. If it’s not in your budget and/or face characters aren’t any of your jam, then Storyteller’s with Mickey & friends in cute camp outfits is the best buffet character dining in DLR (& could probably rival the best at WDW) & not nearly as chaotic as most character buffets are. My DH requests it every couple of trips because he loves the buffet offerings there plus on vacation he loves getting endless Coke/Coke zero refills that a TS meal affords.
I do still think that Carsland will hit with your kids. My DS6 is only very minimally a Cars fan & he enjoys it. Be sure to catch it with the neon lights & if you can swing it, time it to be walking into right at dusk to see the lights turn on to the song. It’s an exact re-enactment of the movie when they turn on the neons & one of our favorite things to do in DCA.
If you have any Marvel fans then Avengers Campus is a hit too, so many roaming characters & good entertainment. We also love the Quantum pretzel and Choco-Smash bars at Pym’s. We didn’t love the bfast at Pym’s but the lunch has some solid (albeit slightly different) lunch choices.
And then if you like snacks & especially theme park ones, DL delivers highly on those. We love beignets & mint juleps, churros, any ice cream, Dole Whip or Dryer’s, corn dogs, turkey legs, corn on the cob (the Buzz cart in Pixar Pier has a chili lime one that is yummy if you like a chili lime spice), Bengal BBQ skewers, most all of the treats at Jolly Holiday, soup bowls from anywhere that offers them (they are all the same Boudin sourdough delicious bread & the soups themselves have always been great too). There’s just so much good food. Maybe that can help entice the family to “put up” with Disney?
Another thing DL does fabulous on that might help with bringing the family is the spontaneous/roaming characters & on more crowded days, excellent atmosphere entertainment too that may combine the characters (have your kids ever played Musical Chairs with Cruella, Mad Hatter and Alice?) that make it easier to keep crowds occupied.
I don’t think you’ll run into crowd issues though going the first week of March. My DD10’s bday is that week and we’ve gone 3-4x for her birthday & it’s always been a nice at most moderately crowded on a Saturday time of year to go. Even less crowds if it’s rainy (which that time of year tends to be a little bit more rainy than the rest of the year). But you have up until the day before you get there for the weather to make up its mind, so even if there is rain in your forecast, just know it could change all the way up until you get there & the only tips I have for rainy days are to have a plan on where to eat since most of the dining is outdoor/indoor combo & if you want to sit down anywhere, it becomes a rare commodity & the limited QS places that offer indoor seating becoming inundated with squatters waiting out the rain.
The San Diego part sounds lovely too so I hope this pans out! SD Zoo is a must-see once in your life & if I ever can swing staying at the del without feeling like the riff-raff dragged in from the tide (how I normally feel at the very start & tail-end of my Disney trips), well then I’d do that too! But maybe just with DH on an anniversary trip or something.