I agree with Steff that you dont need any scripting all You need to do is:
-create a spell (copy actual one with is teleport and add new entry id) and modify cordinates (read spell.dbc on wiki
http://www.wowdev.wiki/index.php?title=Spell.dbc) EDIT. You need to edit some other rows tho i cant really tell You with one because i got own core and table name is just tele_template
-when everything is ready go to Quest template (paste "quest template" in google and find for Your core)
http://collab.kpsn.org/display/tc/Quest+template+tc2
add a spell to req spell cast and rew quest spell cast and You got it
I making boses trash istances everything that i want without using an script language.
Only for Honor exchanger, Arena wiever etc i making C++ scripts.
Later maybe i will make a short TuT for it

Greetings Ayahne
Edit,
If You got an troubles with finding a quest that have cast spell on start and cast spell on end just go around the world in game and search for one