(Auto) Concerns about keeping continuous coverage after selling/scrapping a vehicle. (WA and UT)

Currently residing in WA, but I'm moving to Utah in just a couple of days.

Several years ago, I wrecked my car. I kept the car and was planning on fixing it, but I knew I'd be without a car for a few months, so I cancelled my auto insurance with Progressive. Months later, once my car was again driveable, I signed back up with Progressive, but my rate had skyrocketed! It seems to me that I lost all previous discounts and "tenure" since I had been uninsured for several months.

Fast forward to now. I have maintained continuous coverage with Progressive for many years now. My auto insurance premium is at the lowest it's ever been. I am moving to Utah on Friday and will be "selling" my car to a local metals place tomorrow. Once I move to Utah, it could, theoretically, take me a few months to find a new vehicle. Do I need to maintain continuous coverage (even if I've sold my vehicle) in order to not lose my status and discounts with Progressive? I really don't want my rate to jump when I buy my next car.

If continuous coverage is the way to do that, what do I need to do? My current insurance ends next month (June). I think it might be hard to renew my policy, because won't Progressive know by that time that I sold the car? The only other thing I can think of, is that I will be staying with my father for a few months until I can find an apartment of my own and a new-to-me car. I will be driving my father's car while I am staying with him. What if he added me to HIS car's insurance as a second driver living in the home? The thing is, he's with State Farm, so I still might lose my Progressive discounts.

My head is spinning. I just need to know if there is a way to save my low rate, even if it means paying for coverage I don't need. If having my father add me to his State Farm policy is the answer, will it matter if there's like a week-long gap. I'm not sure if I have to maintain no gaps, or if a short gap is OK.

I'm hoping someone here can understand the situation and knows of the solution. I will take any help I can get. Thank you so much!