Lindsay:
Caribbean Beach Resort would be a solid choice for a trip in March, as one of its best assets, its pirate-themed pool area, would make for a memorable time for your children. Best of all, it has a zero-entry area plus a water play area for young children like
yours. If you splurge to upgrade to one of the pirate-themed rooms, you'll be greeted by double beds in pirate "ships," carpet that looks like plank flooring and other nautical surprises.
Port Orleans: Riverside sports a large pool area called Ol' Man Island. Along with the large pool, water geyser and slide, they have a kiddie pool. There is also a playground nearby if your 2-year-old starts to get water-logged. Port Orleans has two advantages over CBR for you, in my mind: 1) its trundle beds in the Alligator Bayou section. Requesting one of these rooms might alleviate your need for the crib and save on floor space. 2) Its boat to Downtown Disney becomes an attraction unto itself.
I recently found a video of Port Orleans at www.allears.net (look under Accommodations then click on Fact Sheet and it's at the top). You might want to give it a look before making your final decision, but with the ages of your children, either resort will offer you an unforgettable experience.
Wishing y'all a magical vacation!
Whitney