Best way to reach

I am trying to find what's the best way to travel following places at a reasonable price..

Pondicherry to Thiruvannamalai (planning to start around 6am) (100+km)

Thiruvannamalai to Knachipuram (planning to start around 4pm) (100+km)

thank you.

Venum, apologies if this sounds picky--but could you define "best" and "reasonable" for you?
"Bes"t way in tems of confort, convenience, flexibility (able to stop whenever, wherever, on the way) is to hire car/taxi between cities. Cheapest is probably local busses, but itwill take longer and be less comfortable. On the other hand, the bus will be more of a fun adventure!

rebeccam, thank you for your comments. Sorry for not being clear. What i meant was not too expensive. I don't know how expensive is to rent a taxi. Since i have to visit few places in Thiruvannamali, i think taxi would be the best option for Pondi to Thiruvannamali. For Thiruvannamali to Kanchi, it's just a drop off, so it does not matter taxi or bus, but the only condition is timing (planning to leave after 4pm). Is there a direct bus service from Thiruvannamalai to Kanchi and how long does it take ?.

You pay for the taxi's return to the starting place irrespective of whether you use it or leave it midway. So you may as well make use of it.

With these guys that I usually recommend it is Rs 1500 for the 250 km roundtrip to Thiruvannamalai. Maybe slightly more for pick up in Pondy. It includes 10 hours time with the car, the time including the return trip, so if you subtract that, you still have about five to six hours worth of it in Thiru.
http://www.auroville-unity-transport.com/ourprice.html

Finally i talked to auroville unity transport service and reserved car for my trip. They are very good in responding emails and they do take reservation without any pre-pay.

From Pondi/auroville to Thiruvannamalai, bus services offered frequently ?

Take a bus from Pondi, its not necessary to take a taxi. Its a 3 hour journey , there are frequent bus services from the Pondi bus stand ! It won't cost you more than 2 or 3 $ where a taxi could cost you between 50 to a 100 $. The road is rough in some portions of the journey just make sure you aren't seated directly above the wheels. Find a Volvo or a luxury bus if possible.

Thanks, JustDeep.