If your document doesn't need bleed just make sure it is setup at the right dimensions and no objects are overlapping the overall page size.
Resolution wise change the dpi of the original images in Photoshop by going to Image Size then deselecting the resample box, then enter 150 or 300dpi in the resolution option depending on what your printer requires.
Depending how large the scans were in the first place they might become too small dimension wise to use in your designs, if so you basically need proper photography rather than scanned images. Just tell your client this is 2008 not 1998
