Famous Tirupati temple is on the seventh hills of Tirumala. It is better to make darshan in morning time in pleasant weather and sweet fragrance. How much time it will take totally depends upon rush over there. Some ancient temples like Padavati Temples are also in proximity which has great spiritual significance. And if you are ready for a little more travelling (around two and half hours); you can visit to Sri Kalahasti for Lord Shiva temple.