Ok, I just asked the old lady what she recommends. She said to check out
http://visit-stockholm.com/ and click on "What to see". She says that is where she tells everyone to go when asking what to see. I have yet to go there myself, and can't wait! Just looking at her pictures and the pictures of her family's land there is just amazing.
She also recommends Gamla Stan (old town). She also says you can go to the city hall tower and you can see all of Stockholm from there. In a nutshell she says to check out the museums and churches (most beautiful architecture).