The rental car facilities are a shuttle ride away, but are not too bad of a walk, about 5-8 minutes depending on which one you are renting with. They are all along a road. After walking towards the terminal, you'll cut across a parking lot, which goes down a path (downhill) where you cross the main terminal road, and you cross the short term parking lot. I've dropped off luggage before curbside, and dropped off my car. Walking back is about the same time as the shuttle if it isn't leaving when I'm ready. There are also some interesting petroglyphs to the right (side trail) as you're going towards teh terminal around the halfway point.