[amorphous]

The best resource for case numbers, IMO, is https://flutrackers.com/forum/.

I could not find any downloadable corona data at their website. Maybe I'm looking in the wrong area?

[LilFarmer]

Here is a thread with a compilation based on their tracking: https://flutrackers.com/forum/forum/-2019-ncov-new-coronavirus/united-states-2019-ncov/826435-cdc-case-counts-us-15-000-cases-245-fatalities-as-of-march-20-2020/page8#post839319

I don’t know if that’s helpful for what you are doing.