Riverwood, at a glance, is just some quiet, mountain village; but if you look closer you'll see perfect geometry, the converging leylines, the uncanny details; because this isn't just a quiet, mountain village. It is THE quiet mountain village. The archetype for all quiet, mountain villages; the mould from which all others are derived from.
You approach from the west, looking down Main Street (the only street Riverwood really has). To your left is a blacksmith. To your right is a local. Kids play in the streets. Chickens scurry around. Someone out of sight is chopping wood.
Who are you? You're the wandering badass who's just passing through, and Riverwood complements that role perfectly, because it really is a quiet, mountain village. Stay at the inn. Sell some pelts to the merchant. Relax, because unlike the rest of Skyrim, Riverwood isn't terrorized by vampires, or oppressing the Dunmer, or being burnt to the ground by an uber-dragon.
You can wander; in fact, you can just fuck off and go any direction you please; but Riverwood is designed like a funnel. To the north, parallel to the town, is a river, and to the south are mountains. Best of all, when you reach the end of Main Street at the edge of town, there's a bridge. A nice, long bridge that's there to say, "You are leaving Riverwood."
My favorite touch? If you look north, over the river and up in the mountains, you'll see the quiet ruins of Bleak Falls Barrow, shadowing the town like a dormant volcano.
The biggest mistake the developers made was not having the player start just west of Riverwood, with the town in the distance, just down the road; because that's the heart of the game. That's where Skyrim really begins.