The Excel spreadsheet that models the spread of Covid-19, and contains simulations for large and small population and various mitigation scenarios can be downloaded with the link below. Once you have downloaded this file to your own computer, feel free to modify and adjust the parameters to more quantitatively follow past history of the spread in the US. Remember that no model can be quantitatively exact, since the parameters like R0, the initial number of infected people and the timing are not precisly known, and population densities and activities vary across the nation; therefore, the output numbers of any model serve best as qualitative guidance for future actions.
(note: this file was developed in .xlsx, but was required here to be in .xls; if it doesn't load properly on your computer, try saving in .xlsx. If that fails, please send me an email requesting an .xlsx copy)