The nearest metro station is Niuwangmiao, but it’s still a 15 minute walk. I would suggest getting off at the Dongmen bridge station and walking along the river south, then turning left when it joins the other river and you will see the bridge, which is a 20 minute walk. At night this walk along the river is beautiful as everything is lit up. Chengdu is a big city, so depending on how late it is I wouldn’t suggest a solo trip getting there, but once there on the weekends it’s busy as the bar street is next to it. There’s always a bunch of taxis to flag down for getting back to your planned location after the bars!