Keep That Vax Card Close
For starters, if you're eligible, get vaccinated! People who have been vaccinated will no longer need to show a negative COVID test or self-quarantine upon arriving to their destination when traveling domestically. Be sure you always carry your CDC proof of vaccination card. There are currently different digital versions of this that are being developed, such as Clear's Health Pass, or New York’s Excelsior Pass.
For the time being it's definitely best to cover all your bases and always have your card on hand and, if and when you travel, treat it like an extension of your passport.