I was thinking the same thing after reviewing the repo and output HTML but I wonder if that would really lower the monthly hosting costs for the Heroku instance

I was thinking the same thing after reviewing the repo and output HTML but I wonder if that would really lower the monthly hosting costs for the Heroku instance and the various addons. It would be simple to modify the RoR app to output the proper caching headers that would allow any CDN to cache the HTML output and obey the various cache limits, but on demand rendering the output from time to time is still required once the cache expires. I think moving the site to a normal static site generator (like Jekyll) would deliver the most bang for the buck but would be quite the transition. The site would only need to be built upon a new commit and with the proper site generator it will only update the underlying HTML files that require a change. Then syncing the update HTML to whatever CDN is chosen.