I would say if the terrain is stable and plain, then Yelan is quite decent in that, but more than that, it's still not good enough for exploration. Lifeline skill helps to get into a shadow state where she can cover a short distance, regenerate stamina over time, and speed up her movement. It's unlikely that you will encounter such terrain beside the main cities or their roads and may get stuck over a rock or even a stair. So, yes, for short distances, Yelan is good; you can shoot some boxes with her arrows to get the items inside them. But, for overall exploration purposes, there are better characters like Venti or Zhongli. They have much more utility on their plate than an average player.