Well Ranking PDF

I have a PDF which ranks quite well for a few terms although I believe I can improve the content / structure.

That being said, is there any benefit to creating a webpage with the same content and then doing a 301 to that page from the .pdf? Or am I risking the ranking?

Thanks in advance

The advantage of web page is that you can show ads.

But do not redirect. Google is ranking your pdf because google thinks that a pdf report in the search result is appropriate.
You can create a web page with additional content and interlink between the pdf and webpage. Or you can create a web page targeting a keyword close to the one that the pdf is ranking and add a link from your pdf to web page.

Create webpage with re-written or similar content and interlink.

I converted a large PDF that I wrote to html and it totally sunk in the SERPs....

I don't know if I messed up somewhere but the PDF version ranked much better. I reverted it a few months ago and it's back.

Your PDF is probably ranking high due to a QDD push. If you change it to a webpage the rankings might drop.