Program of choice "quick macro" a very light application( not free)
http://www.qmacro.com/
1st. go outside, then come back through the portal then back out, when you are outside type /resign ,this will make u zone the same spot every time
2nd. Set up to do a farm run but make your GW screen small enough that u can run the record tab open when u have the game up.
3rd. Start the record function on the application, now since it tags things easily like collectors/sunspear priest... etc, u may not pick up 100% of all drops ( big deal)
4th. press v to tag the portal door but use your arrow keys to guide you out. start your run as normal but do it in NM mode, run through everything like u would, when u get done type /resign then click to get you back to town
5th.run with your arrow keys in the direction of the merchant, tag him, use your mouse to sell everything, then return to the door.
6th. stop recording
7th, change the F10 start to Ctrl + Z, you can clear it by typing in the field of the program
8th let me know how it goes, its not 100% perfect but one of the better ones I have seen.