In a high canyon in the mountains, the players find a skeleton in a cage suspended from a pole. A few miles further, they find another, and a third contains a partially rotten corpse. The fourth contains a living man who looks as if he hasn't eaten in days. Turns out to be the local way of punishing criminals.
There are more ways than one to encounter a dragon. With a low level group it's obviously not feasible to meet one in its lair and fight it. But standing on a bleak moorland, utterly exposed and vulnerable, it can be a chilling experience to see something flying far far overhead. Something that could just be an eagle, but you never know...