Hi I'm local Shanghainese, hope my advice will help you
小杨生煎is on Wujiang Rd.(also one of my favorite food), it's near Nanjing west Rd., suggest you go straight along Nanjing Rd. and can get there.
Yu Garden will be closed on 17:30. It's very tiny....(Yu Garden is what we called just a garden....) 豫园所在的地区叫作"城隍庙",但这并不只是一个庙的名字,而是整个地区就叫城隍庙.
外滩相比其他大家熟悉的classical 景点, 是我比较喜欢的一个地方,因为比较浪漫,有万国建筑.也适合晚上走走,灯光挺好看.
人民广场你会失望的,上海总体来说除了人就是人,到哪里都看人, esp Nanjing Rd. or Yu Garden area. You'd better watch out your pocket among the crowds.
上海的市区看来看去都差不多的景色. I always recommend my non-Shanghainese friends to visit a place called 朱家角, it's in Qingpu district, about 60 minutes bus away from People Square. Probably it will take you almost a day to finish a return visit back to downtown. It's up to you and you can google the place.
It's vital that whether your itinery is reasonable depends on what kind of place you want to experience and where you settle down so I can help you adjust the place order.
If you should have any problems, feel free to pm me and I will leave my MSN to you. need to sleep now! sorry for the hasty reply : )