Greenfield, WI is a suburb of Milwaukee - It is located just South and West of Milwaukee ( in fact the City of Milwaukee surrounds it) Here is a link to information about the dynamics of Greenfield
Here is the official City of Greenfield Website: http://www.ci.greenfield.wi.us/
You will find all age groups - there is a mix of single family homes, condos, multi-family and commercial areas. Being so close to Milwaukee you have access to all the cultural events in Milwaukee, including Milwaukee Art Museum, Entertainment Centers, Bradley Center- Milwaukee Bucks, Miller Park-Milwaukee Brewers, Summerfest - I could list forever.
Surrounding communities to Greenfield include: Franklin, Greendale, Oak Creek, West Allis, Hales Corners, Cudahy, South Milwaukee. To the North you would find Wauwatosa, to the West New Berlin, Muskego, Brookfield.
I hope this helps. We consider Greenfield as part of the Milwaukee Metro area. I think you would enjoy a visit to the area. If you decide to relocate here, there is alot to choose from.