So your players are still a little on the green side. They’ve heard about Dungeons & Dragons, and have never fully understood the power and nature, and frankly the pure danger of meeting up with a real dragon. They are untrained, a little on the reckless side, and determined to seek out a dragon’s treasure before they are ready for it. I say give it to them, and get prepared for the players to do a lot of yelling "Run away!" Sometimes players need to know that the world they live in isn’t a balanced place, and that there are dangers around the corner that could turn their characters into a fried pie. Falling off the Dragon does just that. With the rumor of a nearby Dragon hoard right from the earliest levels you can quickly establish that you have a dangerous world to contend with.
Enough adventure for an evening or two for 1st-2nd level characters