yah mob hunter is a good quest to try to code cause it uses some interesting stuff.
main things you will wanna make (not saying you don't know this, just writing them down for reference really)
bool controlling if player has quest already
int count for how many kills
str for monster name to be hunting
int for how many kills is required
database function to inport/export and update the values to the character database (or make a quest database, then you can use it for other quests also!)
check when killing mob to see if monster name == monster name required, if so add a kill to the clients kill count and then print out how many kills they have (optional, do an if check to see if it can be divided by 10, that way you only print out how many kills every 10 mobs avoiding spam to the client)
Then obvious checks on the npc to see what level the player is (give them the appropriate monsters to kill), check if player has quest already, update the database when giving/removing the quest from a player, rewards, etc.
Nothing super complex, just a few diff steps to worry about.
If you run into any snags lemme know and I'll load up a source and see what I can do for you.