As I remember, 7th Guest and 11th Hour were just collections of PopCap-type games embedded in an uninteresting and/or poorly told story. Kind of a half-step between a puzzle game (like PopCap-type games, Lemmings, or Bubble Bobble) and adventure games (like Zork or Space Quest).

As such, it's kind of hard to tell which sort of game she likes. Myst also sorta lives in that area, but leans more towards the adventure game. I'd try that (you can get the original remastered for modern OSes these days) and see if she likes it. If so, I'd steer her more towards the adventure game side. If not, more towards the puzzle game side.

In either case, Gamespot has a listing of games by type and it includes both adventure and puzzle.