There is really only one ride at Toontown: Goofy's Barnstormer (a child-friendly roller coaster), and I don't think you'll have a long wait visiting in early February. In addition, there is a water play area which I imagine won't be too appealing in February and a play area called Toon Park for little ones under 40".
With this said, there is a great opportunity to visit characters here, and this will be where much of time could be spent. Guests can tour Minnie's house as well as Mickey's, which leads to a meet and greet for Mickey. Additionally, in the Toontown Hall of Fame there are 3 different areas for character greetings with one of groups usually being princesses.
So with all this said, I would estimate to spend at least an hour at Toontown with the possibility of more time if you discover your daughter wants to meet at the characters or has fun playing at Toon Park or exploring Mickey's and Minnie's houses
Toontown opens an hour after the Magic Kingdom opens for all guests, and it can be fun to be at this rope drop since oftentimes characters help to welcomes guests. .