Weekend in Edinburgh with a day trip to Glentress?
The blue is really fun and the red isn't too hard, nothing you can't roll over. Its possible to mix and match them as well so you could do one section of the red and if she didn't like it go back to the blue. There are also some nice skills loops, rated green, blue and red, which you can easily spend a few hours on.
The red was my first ever mtb ride and I loved it even though I'm GASP...... A GIRL!!!!!!!