From Dick Atlee:
There is a very helpful interactive map at
https://wanderlog.com/covid-us-state-travel-restrictions
which, if you tell it where you’re coming from, will tell you what, if any, entry restrictions exist for any state you click on. As of now, it was last updated on 9/22; I don’t know what its history of updatedness is, but it seems a lot better than nothing.