thanks here is enough. you’re welcome, and i’m glad it works for you.
one thing that i was thinking about is that the page that you put into the iframe could theoretically be called by third party sites, which you may want to prevent. i didn’t include anything in the code above to prevent that, but here’s some discussion about ways to do that, i think: https://stackoverflow.com/questions/21751377/foolproof-way-to-detect-if-this-page-is-inside-a-cross-domain-iframe.
also note that the code above still contains a lot of different map tile layers. if you don’t plan to use them, you could remove them from your version of the code just to keep things less cluttered. as mentioned before, feel free to tweak the code (except the third party attributions).
your website looks good. i wish you the best with that project, and the book, too.