This Method is the most fun way to get under SW with almost no effort.
What you will need
wallclimbing hack
a 60% speed mount
Nogg
ok heres how u do it: first go to Blackrock mountain and start wallwalking to the very top ( you will go by Nafarians chamber on the way up) and when u reach the top point yourself to the placeholder above Elwyan Forest. no get ur slowfall on and iummediatly mount up run and jump of then u fall for the full 2 min and should land on the group loseing about 40% health and then run towards SW and u are under it :P
P.S in nafarians chamber there is a spot where u can fall through the world and land in that chamber below it (kinda kool trick)