The lakefront path is popular for bikers in the summer and sometimes, a little too popular. If you'd care to avoid the bladers, the joggers, the walkers and the kids whose parents don't seem to hold on to when walking the path, always refer to the Chicago Bike Map for various routes around the city. Dan Hosek has a brief list of routes with descriptions going east-west and north-south. It gives you an idea of what a proposed bike route might be like.