Is there a pdf crop utility for windows that will give smaller files?

Use BRISS:

It's light and free. And it's portable (you don't need to install anything). I tried it on Windows 8.1.

You can download it from here and run it:

1- "l": load

2- "cancel" (or enter page numbers to be excluded).

3- Adjust the top-left and bottom-right corners of the desired rectangle with mouse.

4- "c": crop and save the cropped file.

Check out PDF manipulation tips, Part 1. I haven't used this functionality before myself, but ghostscript can apparently handle this from the command line with:

gswin32c.exe -sDEVICE=pdfwrite -dMaxSubsetPct=100 -dPDFSETTINGS=/ebook -sOutputFile="outfile.pdf" -dNOPAUSE -dBATCH "infile.pdf"

where -dPDFSETTINGS is used to define how images are resampled. Using -dPDFSETTINGS=/screen will yield dpi=72. I just tried this with a sample pdf and it seems to work fine.