How can I download a PDF of just a past Federal Return? I don’t want the PDF file to include all the pages from my State return. And that’s what’s happening

Sorry there is only 1 pdf with both returns and backup pages.  You can print just the pages you want.

If you want a pdf you would have to print out what you want then scan them into a new pdf file.  If your printer doesn't scan you can go to an office store like Staples or Kinkos.

Most PDF readers will allow you to choose what to PRINT then save them to a separate PDF under a new file name.  This saves you the paper & ink and bother to scan & save.  

Each year, prior to the end of filing season in mid October,  one should always save a PDF of the return with and without the worksheets for future needs.   Once the season ends the only PDF available is the larger one with everything.