Research shows that wearing your mask, and opening the front passenger window, and the window behind the driver seat helps to reduce the spread of the novel coronavirus in your vehicle. See this NY Times article.
I need to travel to California end of may or beginning of June and would like to maybe see Colorado and Utah on the way, but I am totally flexible, if you'd rather just go through Arizona and New Mexico. I'm also going to have some luggage, so if your car isn't too too small, that would be great.