1-2 hrs by bus or < 1 hour by car from Hangzhou downtown. it's on the north east. 

There is a long river (which is the south end from beijing to hangzhou) and an old stone bridge and other interesting place around them to tour. Usually one day is ENOUGH !

BUS LINE : airport bus to Chengzhan ( main train station in downtown ) and take bus 88/K88 to Da Guan Bei ( terminal bus station) then take bus 342/K342 to Tangqi ( terminal bus station).

CAR: check via hi@itangqi.com in advance to see if available and the fee will be covered in the whole Tangqi trip. Cost: below 400 RMB / person.