I love driving the Z in E. Texas. There are some amazing back roads without a single car for miles, nice sweeping banked curves, friendly people at every little family owned restaurant.
The Hill Country is also great place for the Z to stretch its legs. The 'Devil's Backbone' is a great drive and a tour through Wimberley, Luckenbach, Enchanted Rock State Park, Marble Falls, Lost Maples State Park etc. is in the works