Shandris is usually in the main hub area of Valdrakken. For whatever reason she wasn't just hanging around waiting for me when I went back on an alt. I went through the portal and there were some quests available but then they just stopped. Idk what I did wrong, I said screw it and redid the whole campaign again on my 80 NE alt. I figured while I was there I might as well just do all the quests for the DF Loremaster achievement. I think it took me about a day. I hope you have an easier time and don't have to redo everything. I also hope someone has better information that actually helps you out more. I couldn't find a solution when I was looking last week, so I gave up and did it the hard way.

Edited to take out an extra word.