How did you play when you were growing up? How important is play time? I personally think independent play time to build imagination and personal creativeness is very important for our girls and for their mother.
The girls have recently dug out some of their old farm toys and their dad's old farm toys. Then they added some Barbie cars and Polly Pockets and voila!
I grew up with one brother and one sister so we played a lot like this, dolls and tractors together at the same time. It was a compromise, even though we didn't know it at the time. I was constantly putting dolls on his tractors. They usually had green paint though.