Sheet Viewport Too Big

How to resize viewport (efficiently)? If viewport is "bigger" than sheet, go into that view and check for hidden items, "Reveal Hidden Elements" button at bottom of model window. Move / delete them if you can. The view port sizes itself according to what is in that particular view EVEN IF it's hidden.

"Crop View - Select the Crop View check box to enable a crop boundary around the model. Select the boundary and resize it using the drag controls. As you resize the boundary, the visibility of the model changes. To turn off the boundary and maintain the cropping, clear the Crop Region Visible check box. See Crop Regions."

ref: http://docs.autodesk.com/REVIT/2011/ENU/filesUsersGuide/WS46b90c3cb2c58cad922804fc7fa4315f-7f88.htm