To do this yourself, wall-jump up following the arrow. Both sides seem to have an invisible wall halfway up, and at the front side my bud had a lot of trouble climbing the opposite side to me. When he tried this side as I did, he climbed like a squirrel on speed. Not sure whether this side is just easier for wall-jumping, or he just had bad luck on the opposite side however.
This is fun for watching who's coming through, especially if you can stealth, and my next plan is to take a level 1 to the Outland's side and park him on top of that portal to greet players as they come through.
I realize this is probably classed as common sense, but the tag should say it all. I'm proud I made it up there.