I think it is easy enough to fill a place full of monsters to fight, but finding meaningful RP interactions will be the challenge. I have a few ideas:
1) An older bigger (but still small) dragon who beats him up and rummages through his lair stealing all his good stuff. Do this early so that he does not lose too much loot, but is always afraid of the guy coming back. Have the bully dragon travel through his lands again later, so he has to hide himself and his horde. A few instances of bullying later and you have made a great rival that the PC cannot wait to grow up and beat.
2) A Kobold clan, particularly their evil Tiamut cultist shaman. The Kobolds know that dragons are above them, but they have a plan. They want to nicely 'control' the dragon and train him up in the ways of Tiamut and fight for them. That way when he grows up, they will have a protector who is loyal to them and sees them more like family than minions. The sense of family will be tempting, but the Kobolds want the dragon to do some horrible stuff. The Kobolds act as guards to the lair etc, but it is clear they take orders from the shaman and the dragon could find himself under unofficial house-arrest.
3) A group of wandering want-to-be heroes who think that all dragons can be killed for glory and loot. They are not evil, but have read way too many fairy-tale books. This could be used to inject some comedy, but if handled poorly they are a match for the dragon. If the dragon is violent to them, more people from the village/nomads will come hunting.
If the dragon talks them down, they share that their village is under threat and they are out to prove themselves heroes to the shaman. The dragon might even want to help them and end up with some allies.
4) A ratbag noble on his errancy quest. He does not care that the dragon is not evil, he just thinks its head will make a fine trophy. He is a coward and a woose, but has brought some very mean mercenaries with him (breaking the rules of the errancy quest). If he is hurt much, daddy who is a powerful baron will be most displeased.
5) A run-away princess who fell in love with a charming bandit, but he took off and she has been left alone in the badlands. If the dragon rescues her, he better watch out, noble knights are coming hunting for her. To complicate matters, her evil step-mother would prefer she was not ever found and has sent some people of her own. Can the dragon tell the difference?
Will the dragon end up with a friend in the princess? Will she be insufferable? If he goes out to hunt to feed her, then what if the bully dragon comes back? Maybe it will steal the princess. Then when the tracks lead the knights to the PCs lair, how the heck will he explain that, would they bother to even listen? What if one of them is the princesses' brother? She might not like it if he is beaten up