Here are the command-line switches you can use to tailor Windows Explorer to fit your needs:
/n opens Windows Explorer in single-pane view, which is similar to the view you see when you open My Computer.
/e opens Windows Explorer in multipane view, which is the view used when you open it from the default Windows Explorer shortcut on the Start menu.
/root,<object> specifies the folder that you want Windows Explorer to use as the root for the view. For example, you might specify a UNC path to open Windows Explorer with the shared network folder as the root of the view.
/select,<sub object> opens Windows Explorer with the file, folder, or application specified by <sub object> selected.
I see no switch for the window size, though. Yet, the Explorer remembers the mode in which it was used the last time. So if you close it while in maximized state, it will open like that again.