What are the differences between the two usages? From what I've surmised, the meaning is more or less the same. Typically, I tend to associate this usage of 行く to "moving away" from the speaker (e.g. 歩いていく), but that doesn't sound right here.
For context, here's the original sentence
ハイキングに出る時も、もし、不安{ふあん}だったら、リュックに鈴{すず}を付{つ}けて行くといいよ」と言った。
Rather than the ～て行く or ～てくる grammar points, this is just the conjunctive て. I think it would be easier to understand if the sentence was written like this instead:
リュックに鈴を付けて、行くといいよ。
It would be better if you stuck a bell on your bag and went.
行く here is being used in a literal sense. "stick it on your bag" and "go (hiking)" are separate verbs here.
