Is there a way to access the version of my return with the one-page summary and thank you letters after I've submitted? The download option after filing is forms only.

Try this method to get the cover pages and even worksheets, if desired. 

Here's how to open your return back up to go the Print Center where you can choose various PDFs.

NOTE:  When you open your return back up, do not make any changes in it since it's already been filed.

• Log in and go to "Your Tax Returns & Documents."  Click that line or on the word SHOW to expand that section.
• Choose 2018 tax year.
• Click on "Add a State."  (you don't really add one.  That's just to open your return back up.)
  
• After the return is open, click in the left menu column on TAX TOOLS, then PRINT CENTER.
• Then choose "Print, save, view this year's return."
• The next screen should offer 3 options:  "Just my tax returns", or "include government worksheets (optional)", or "include government and TurboTax worksheets (optional.)"
• See if one of those PDFs has what you need.
  

NOTE:  Do NOT use this method to open a return to make changes/edits to an already-filed return (one that has actually been mailed or efiled.)   If you later need to make changes to an already-filed return, you have to go through the formal amending process, and your return must start off exactly as originally filed.

That did the trick, thanks!

Great!  I"m glad it worked.  You're welcome.