The heart of Kirkland near Downtown and close to City Hall is built out on a grid, so cul de sacs are pretty non existent. It really depends on the price range and how close to Downtown you want to be. You don't see "cul de sacs" much until you get into tract housing.
Best to start with which schools you want to consider in Kirkland and then move to commute issues when determining which neighborhood. Unlike the good old days, kids are not necessarily all over the streets in this rainy area on a year round basis. You can go to most any neighborhood almost year round and not see a lot of children outside on the streets.
How old are the children? Turtle Park on 9th in Norkirk-East of Market is a favored park for small children near Downtown. The 2nd favorite park that is for small and slightly older children is in Rose Hill. If the children are over 8 or 10 years old, activities and favorite parks depend on their areas of interest.