How did the ancient people get connected by road in the subcontinent of India?
We have records of Kings and people of various kingdoms,they were fifty six,spread in the North,East,South and West .
That too in a vast stretch of land.
Tamil kings of yore,from Udiyan Cheralaathan,who provided food both for Pandava and Kaurava armies,traveled from the Chera Kingdom,present Kerala ,at the bottom of Indian subcontinent,to Kurukshetra,near New Delhi in the North India.
So did Malayathwaja Pandya from Madurai, Tamil Nadu to New Delhi to take part in the Epic battle of Mahabharata.
Senguttuvan, A Chera king traveled to Himalayas.
Lord Rama,Krishna,Bhima,Arjuna,Sahadeva and a host of ancient Indians traveled throughout India either as Pilgrimage or a part of their assertion of their Suzerainty .
Then we have Chandragupta who traveled to South.
How did they travel?
Were there roads?
There were two highways.
Ancient India, according to Mahajanapadas, Footprints of People or Kingdoms,was divided into Five parts.
Vedic divisions of India.
Puranic Divisions of India.
This period is tentatively dated between 1200 to 600 BC( https://en.m.wikipedia.org/wiki/Iron_Age_in_India )
Taking into consideration that metallurgy was present in these period,the civilization could have been older with infrastructure like roads.
So the highway may be dated conservatively around 2000 BC.