I wonder how much of it is the individual child. My dd always followed me, cried if I wasn't down on the floor so I always played with her until she got much older but my ds is fine to play alone and will play for ages with his toys. I often just sit and watch him as I'm amazed to see how he uses different objects to play with.
I often start out with putting him down with whatever objects and I'll show him what I would do (as I'm curious to see if he'll follow to do his own thing). I also put down a variety of items at one time but spread out so he has to move to them, ie. his piano, his truck, hard building blocks (which he just loves to chew and bang the truck with), soft blocks, hard paged books and even some wooden spoons. Our house is open concept so I can cook dinner or tidy the kitchen while he's playing but still keep an eye watching him at the same time. Don't think he'd be a happy camper at all if I left the room, but I can't leave him alone as we don't "baby proof" the house as we prefer to teach them not to touch what they shouldn't and as a result he can never be left alone.
I would try putting down a variety for her, spend 5 min on the floor with her, but then remove yourself to another part of the room once she gets engaged, come back if she fusses, walk away once she's engaged.
