Susan:
With three small children, I think your approach to have more down-time is an excellent one, and since you'll probably have two in strollers, choosing a resort that doesn't take a lot of time to traverse is certainly wise.
Two resorts come to mind: Caribbean Beach Resort for its pirate-themed pool and Port Orleans for its ferry to Downtown Disney. Although CBR sports the best pool area in the Moderate category, especially with its pirate-themed splash area for toddlers, it definitely scores lower than Port Orleans for additional activities and sprawling size.
Port Orleans is divided into two campuses: the
French Quarter and
Riverside. You'll have to compromise no matter which side you choose. The French Quarter is considerably smaller and the theming more unique but its pool is ho-hum, even with a large slide. Riverside's pool area is large (although you can stay at French Quarter and visit it) but its campus is larger, although not as vast as CBR.
What sets Port Orleans apart from the other Moderates and therefore puts it over the edge as my recommendation? Its ferry to Downtown Disney. My children love to ride it, and I admit I do, too--especially at night when you can enjoy the lights of DD from the lake. None are the perfect choice, but my initial thought is a double room at the French Quarter in a centrally-located building like 4 or 5.
Wishing y'all a magical vacation!
Whitney