I’m running D&D 5e in an original setting 

that’s built specifically for a West Marches-style campaign, and I wanted to give the players something that might explain why they choose to stay in the frontier city.

The Harrowing Journey is the result of that effort. It’s been used both in a group prelude and as a solo after-the-fact tool, and in both cases the results were useful and entertaining. The rules are not specific to 5th Edition, nor indeed to D&D. All that’s required is a place in your setting where people are much more likely to fall afoul of terrain, elements, and monsters than usual.

As an aside, if a West Marches style campaign sounds like fun to you, why not helps us build one that spans the entire community in the province? You can find a group trying to do just that at Marches on the Rock….