It's really what you want for a true getaway, undisturbed by the outside world. Most people who come here take a trip to Punganoor Lake for a boat ride next to a children's play park. It's easier to reach Yelagiri Hills and its central town of Athanur by car or train (Jolarpet) than it is by bus. From Chennai, it would take all day to reach your destination.
If you wish to drive from Chennai, Yelagiri Hills is accessible by State Highway 113 and SH 57 to National Highway 46 and then SH 122. The last part of the journey will be along a winding, twisting road with lots of opportunities to see monkeys, although it's highly recommended not to get too close. Scenery is the main attraction and the cooler temperatures, especially during the "winter" months. Bring a jacket, especially for nighttime.
There are several hotels including a small Taj resort and the popular Hotel Hills and the Hotel Yelagiri, about 30 places in all where you can stay, but some have far superior accommodations than others.