The key to Princess and Find Rolf's Body is to show no mercy to the mobs that could later come own you. Murloc camps are hard pulls, but if you have a buddy with you (preferably a healing class) it should be easy. Pricess's farm isn't that hard. Going in kill the two defias by the wagon, then the defias around the house, and finally the defias inside the house. Then kill and shift-rightclick loot (instant loot, the window doesn't come up, 'tis useful) and then even if her bodyguards kill you, you've still go the loot. You've gotta prioritize what mobs you'll kill if it's clearly suicide.
What server are you on? If it's Thunderlord I'll be your hitman as soon as I resubscribe.
EDIT -
Seeing as how nobody answered, apparently:
Instance are a dungeon, or a castle, or something with a series of mini-bosses (extremely hard mobs that drop good loot, relative to normal mobs) and are filled with "elite" mobs (harder than normal mobs), which finally have a boss that's usually entwined in a bunch of quest lines in the area. They're called instances because for each group (usually 5 men, eventually you'll do ten-man (Blackrock Spire) and 40 man (Molten Core, Blackwing Lair, Naxxramas)) theres a seperate "instance" of the area, so nobody else can come in and kill your mobs.
A list of low-level instances:
The Deadmines (Level 20, Westfall), hideout of the Defias, run by Edwin VanCleef.
Ruins of Gnomeregan (25, Dun Morogh), trogg/radiation-infested Gnomish city. I don't think it has one main boss, but several mini-bosses.
Scarlet Monestary (Level 33+, Trisifal Glades (Horde territory!)), four instances inhabited by the Scarlet Crusade, the "zomg the world is full of evil undead people in disguise!!!!!!" paladins who survived the scourging of Lordaeron (the big castle you'll see when going up there).
