Upvote:2
While Uber/Lyft are generally focused on urban areas, their coverage areas can include fairly rural parts.
Greyhound, Trailways, and other bus lines serve many rural locations on and off the Interstate Highway System through extensive partner agreements with local or regional operators.
Amtrak travels through many rural areas, not being connected to the Interstate system at all. They also have partner ships with regional Bus operators allowing you to book combined Rail/Bus itineraries.
While these are great for getting to/from even very small towns, you may still have to search for a local car service/taxi to reach specific locations such as a remote cottage.