What is the word meaning "going on and on for miles and miles"?

Edit: I was walking down an intolerably long sidewalk one day, and every time a mounted another hill, I saw more of it seeming to stretch out before me. It got me to thinking: is there a word for "going on and on for miles and miles?"

I'm looking for a single adjective that is aptly descriptive of a road that stretches for miles and never seems to end. I tried various words already; for example, it can't be ramifying because that word means branching out in different directions. Neither is it redounding, which has the idea of repetition. Long or lengthy would be too plain, while at the same time not saying enough.

So what I'm asking for is a single adjective (or present participle) that applies to a road or path and describes it as stretching out ahead for miles with no end in sight in a single word. Does this word even exist? If it does, what is it?

Example: It was a long road, stretching and ___ing as it went, and it seemed like it would never end.


Extensive, far-reaching, vast.

The other answers that propose expressions of infinity, timelessness, perpetuity, unending, etc. are off-base, IMO.

The question says that this extends for miles and miles.

  • It says nothing about going on forever. It does say no end in sight, but that is not the same as no end.

  • It clearly is about space, not time.


Interminable

From the Free dictionary:

  1. Being or seeming to be without an end; endless. ...
  2. Tiresomely long; tedious.

We've been driving for hours! Every time we round a bend or top a hill, the road just keeps going. It's interminable! It goes on forever!

Edit after the question was revised:

It was a long road, stretching interminably as it went, and it seemed like it would never end.