I went to Yelagiri from Chennai in October 2009 by car. The route is Chennai-Kanchipuram-Vellore-Vaniyambadi-Yelagiri.The road is excellent upto Vaniyambadi.
From Vaniyambadi one has to leave the highway and take the Ghat road for 22 kms upto Yelagiri.The ghat road is narrow with sparse traffic. There are view points at regular intervals. At Yelagiri I went to hotel O nila since there were numerous sign boards advertising the Hotel.
As I had not booked in advance they told me that rooms would be available only at 3pm. I had to wait for nearly an hour from 3pm during which time they told me they were cleaning the room. The rooms are dirty, foul smelling and not worth the amount they charge (Rs.1500 + taxes). The bathroom is very dirty and doesn’t even have a ventilator. Food is compulsory from the hotel charged at Rs.400 per person. Quality of food is not good, my wife found a thread in the chicken dish.
The waiters serving food at the buffet serve only very small amounts and reluctantly serve more only if asked repeatedly. For the ridiculous amounts they charge they should not make visitors feel like beggars.There is a small swimming pool which does not have facility for filtration, chlorination etc (God save those who swim there) and a park for kids to play. The cottages are still being constructed.So expect a lot of dust and noise. I would not recommend this hotel to anyone.
Yelagiri was cool and pleasant especially in the afternoons. There is not much sightseeing to be done here apart from the lake and nature park. There is a tourist information centre and sunset point opposite that. There is a small lake at Nilavur (3kms away) not worth visiting.It is more of a mud pond. Trekking can be done upto Swamimalai, the highest point.For this one has to go upto Mangalam village, park the vehicle there and ask the locals for directions to Swamimalai.
The best thing to do is to book Yathri Nivas in advance and then make the trip by own vehicle as public transport is not good. Another point to take note is that there are no fuel stations in the hills. So it is a must to fill up fuel in Vaniyambadi before climbing uphill.
Credit/Debit cards are not accepted anywhere in the hills so carry enough cash. There is a newly opened SBI ATM.