Winter Park has excellent beginner terrain. There is a section of the mountain near Snoasis called Discovery Park that has three, maybe four lifts that serve a variety of easy, beginner runs. It's nice because it's segregated but the beginner isn't relegated to the bottom of the mountain. Means you can ski intermediate or advanced terrain and still meet up at Snoasis for lunch or whatever. After she graduates from that section, there are also some more advanced green runs that parallel blue ones nearby.
It is easy to find your way around and regroup, as long as you stay on WP mountain.
They also have a very good ski school...
The only drawback to WP beginner terrain is the run back down at the end of the day is a bad choice between horribly crowded or impossibly flat.
Lastly, my experience has been that the snow quality is better at WP than at Keystone. I consider myself an advanced skier and even I was nervous on some of the easy runs navigating around Keystone - too many different levels together not paying attention.
Did i mention they have a great ski school?