Having dated women in the past with young children I think it's actually easier for them when they are not of school age.
(No homework or after school activities to rush them to)
Most dates take place after 8PM and toddlers are usually put to bed by then or soon after by a babysitter, aunts, or grandparents.
In other instances if there is co-parenting between the mother and father some women plan their dates around days/nights they don't have the child. It's also healthy for the child to spend time with their father. Ideally a child should bond with both parents.
Leaving kids with sitters helps prepare them for school separation.
If the dating evolves into a relationship they introduce the child to the man and gradually include the child on some daytime outings.