Driving across the country on your birthday is not exactly the funnest way to spend your birthday. I imagine you'll really feel over the hill after the drive, your back will hurt and your muscles will be stiff and achy. It won't all be due to the Minnesota cold and humidity - remember you're fifty now. You're over the hill little sis, whether you like it or not.
At least you no longer have to work. Being retired will rock, except for the no money part. Oh, but that won't even be bad because that police pension will be sufficient to keep you out of the poor house. Now you just have to learn to budget a little. Knock off the starbucks.
I'm a little jealous you don't have to work - but you will have a trying year. It is quite the adventure moving across the country. Your relocation to AZ retirement haven, will hopefully go as smooth as possible, but there will be days you wonder what the hell you signed up for (like when its 120F in the summer). I know you'll make it though.
Enjoy the journey, it's not all about the destination.