Heijing (黑井; Hēijǐng) is a city in Central Yunnan Province.
Possibly the fastest way to get to Heijing from Kunming is to get a fast train from Kunming to Guangtong (1.5 hours) and then a bus to Heijing (1.5 hours).
At the train station you'll probably find horse carriages and mini buses waiting for you. A horse carriage into Heijing costs ¥5.
There is a city entrance fee (30 rmb). The horse carriage/taxi will stop at the ticket office and make you buy a ticket before driving on into the city. If you get the bus to Heijing it may not stop at the gate to make you buy a ticket, however you will need one if you want to visit the Wu house, the ancient salt factory or the guild hall. You can buy the ticket at any of those places. The ticket has a handy map of the town printed on the back.
Once you're in the city you'll be able to and will have to walk everywhere other than the old salt works, to which you can take a horse carriage.
The main thing to do in Heijing is to walk around its alleys. The old salt works outside town also has an interesting display on the history of the town (Chinese only).
Sometimes there is an animal market under the train bridge near the north end of the city.
There are pavilions, pagodas and temples in the hills around the old town to which you can hike.
Heijing is famous for being the salt city and you'll find souvenirs made from salt everywhere. There are things like kitschy hearts, little Confucius statues and bowls made from salt.
Heijing has several local specialities (mostly involving large amounts of salt) which all the restaurants on the main street sell.
There are simple rooms in regular guest houses (also on the East side of the river) for around ¥40. Alternatively you can stay in one of the big old courtyard houses for about ¥200.
Buses and horse carriages leave near the bridge in the south/center of town. There are buses to Chuxiong.