If your MK day falls on a Sunday or Thursday, those are Extra Magic Hour days for MK (resort guest early entry). Fantasyland is open for EMH, which makes it easy to get to Peter Pan, Winnie the Pooh, Dumbo, and It's a Small World without long lines. Other must-dos for that age group:
~Mickey's Toontown Fair- you can visit Mickey's house, Minnie's house, Donald's boat, and your 3yo may be big enough to ride Goofy's Barnstormer (a pint-sized rollercoaster that looks like an airplane).
~Country Bear Jamboree in Frontierland.
~The Enchanted Tiki Room (under new management) w/Iago and Zazu, The Jungle Cruise (gentle boat ride with minor bit of darkness), and the Magic Carpets of Aladdin in Adventureland.
~Liberty Belle Riverboat in Liberty Square.
~Tomorrowland Transit Authority (peoplemover) and Buzz Lightyear's Space Ranger Spin in Tomorrowland.
~The WDW Railroad.
~Main Street Vehicles or Horse-drawn trolley on Main Street, USA.
~Belle's Story Time in the Fairytale Garden Theatre (to the right of the castle).
~Ariel's Grotto (meet The Little Mermaid) in Fantasyland.
~Share a Dream Come True Parade (daily at 3pm).
You and your husband will probably also enjoy most of these attractions.