The road condition is very good from Cusco to Chinchero. For the Sunday we went there, besides beautiful landscape, local people, occassionally cars/tour buses, bikes(!), there was hardly any traffic at all.
Most tourists come to this town for its Sunday market, and most of the tourists coming to town by tourist buses (seen in the background, outside of the wall of the market place).
One can also hire a taxi from Cusco to get here.
Others may inform you how to take a bus from Cusco.
There is really no need to take a taxi or a tour to Chincheros. There are plenty of buses making the routes to and from Cusco or Urubamba several times per day. Just flag one down and expect to pay under $1 USD per hour. The ride from Cusco to Chincheros takes under 1 hour.