And speaking of that, what is everyone packing for March weather? It is going to be so hard to prepare for 70s during the day & 50s at night!
It's not that hard, really. Personally, I wear lightweight capri pants with a short-sleeved shirt, and bring a windbreaker and/or sweater to take on and off as needed.
The boys wear longish shorts, a t-shirt, and they wear or we bring windbreakers for them.
(See the pic from DisneyDreaminAubrey for the classic, practical, yet always fashionable way the Disney mom dresses her Disney sons!

Note the shades!)
We all wear socks and sneakers all day, for warmth and comfort.
I usually carry a backpack with their jackets, suncreen, juice boxes and snacks, a couple of water bottles, while DH (back in the day -- when the boys were 5 and 3 and younger) pushes the double stroller.
If we are going to a place where wetness may occur (Epcot, on bridge to WS, and Kali River Rapids in AK are the soakers for our family, not to mention Donald's Boat in toontown or the sparying water spouts in Adventureland), I bring the boys extra clothers and a ziplock bag, sometimes even a medium sized towel. You may not dry off as fast in March, so we find it important to be prepared.
I think for March, making sure to have a couple of light sweaters/sweatshirts and a windbreaker, plus one rain poncho, is a good plan. You may not need them, but you have them if necessary.