R.D.
It's the quality of time you spend together, not the quantity.
I work from home, so I'm NOT at my son's beck and call. He has to entertain himself to a certain extent. When I'm not working, he helps me unload/load the dishwasher, helps carry the clean, folded laundry to the appropriate rooms, we read books or play short games, etc.
But again, for the most part, he's pretty independent, especially for that age. Best thing to do is cut her loose and see what happens. If she demands you play with her, SHOW HER how to play, then tell her to do it herself. It's not going to be easy at first, but she'll get the hang of it, and before you know it, she'll start applying her own imagination. Next thing you know, you'll be begging to participate ;)