We spent the summer wandering around the upper rocky mountain states with no problems, and plan to leave on a trip to the southern western states within the week so I'm not really sure what you think is closed down. Yes some national park visitor centers are closed, but not all and the parks are mostly open with the possible exception of Cali. Hard to say what's going on there tho the just loosened restrictions today. NM reportedly just loosened restrictions too. So there is plenty to do out there.
Key West is a day or two to see everything and also it is the peak of the snowbird season and you will find camps mostly full and extraordinarily expensive if you do find a spot. Wait until April for the Keys