I just finished playing Firewatch, which I really liked. It is a game that essentially tells a linear story, but does a good job of making you feel like an active participant. Traversing an open world goes a long way towards that, but it is mostly achieved by building a meaningful relationship with another human being. The quality and nuances of the interaction with this other person is probably the most player-pliable part of the experience. We tried something along the same lines once.
Licensing music is expensive and generally far outstrips the cost of licensing sound effects. Sometimes it is possible to find a few decent sound snippets in effect libraries that can effectively sequenced to create decent music track. One example is a track I put together for a promo video of Mahjong Seasons, combining a Chinese flute recording with Asian drums and cymbals.