Pretty sure when you kill a boss, they drop the item that you can exchange for exp which are part of the RTF quests.
You can get a RTF when you kill the giant serpent (not sure if it's a different mini in SZ) and I remember I've got another one while killing blind madmens. Right now the problem is that they have a special drop to start those quests and with this bloody low drop rate, it's hard to get it -.- There are more RTF quests, but I can't remember right now...
In SZ, it's a giant tarantula xD but I can't even seem to find it lately, nevermind miss out on its stupid low drop rate. Datong RTF, I believe kill lightning shadow disciple for drop (forgot name), then you meet a guy in 1st village (Quest name something about a "braggart"), and just follow from there (a) kill superior lightning shadow master, b) kill bloodthief disciple, c) kill howling raider, etc)
