For view options you do just that. Go to LW's menu & View & Show/Hide. Here you'll see Library window etc.
I'm not sure why you were so concerned about people browsing your shared folders. They're there for sharing aren't they? Only share files you want to share. Your shared folders are listed in your Tools-Options-Sharing. These folders can be added or deleted anytime from the list using this Sharing option preferences window.
The only files you can view in your LW library window are ones you share & your incomplete folder. If you wish to have your LW dwnld folder listed in the library you'll need to share it. Click here for instructions & sample image

By the way, the new beta versions of LW by default have a Saved files folder listed in the LW Library window. Which is equivalent of what you want. So then you can open your dwnld folder simly by using the Explore/browse button from the Lib window.