Um, try googling homeschool preschool. I bet there will be some ideas for indoor creative and sensory play. They had a sand table that would morph into a water table after a month or so and all sorts of other textural activities at my kids preschool. Along the same lines, I used to strip mine down to a diaper, put a sheet on the floor and let them finger paint to their hearts content and just throw them in the tub after. It was mostly just squishing the paint around, the way it felt in their hands and on their bodies, that was interesting.
Also try rotating toys. Put a small box of toys out. When she tires of those, put them away and take out the others. That way something is always "new". Also makes tiding easier since there is less junk to get disorganized. And stuff that is not typically called a toy like a magnifying glass can start to be fun at this age with proper supervision.
I wouldn't worry too much about not having too many other kids around at this age. From what I have read, kids don't really start to develop social skills until they are three. Before that, preschool is mostly either daycare or mother's (father's) day out events. She will get every virus known to mankind for a bit once you around more people since she has been fairly sheltered.
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