If you are going to go with the redwood chips, make sure you lay down weed fabric so that the weeds, grass, and so forth do not come through the chips. Astroturf can be very hard to maintain if you do not know how to take care of it, if you do then try that. Also, if you are willing to put some work in it at first, you can always make a rock garden in different areas of your yard. Just strip out the grass in the areas you want, lay the weed fabric, and lay the rock you want. HINT: put some kind of border around the rock in order to keep it in the designed area so that it will not get in areas where you do not want it.