Leaving June 4th and just looking for last minute ideas / help

Hello Everyone, This is my first post on RTA forums. My Fiance and I are making our first cross country road trip and we are both nervous about making sure we have everything ready. I guess what I am looking for is some helpful advice like things to do, things to stay / places to stay away from. Maybe something you would have wanted to know your first time.
I am currently doing a full tune up on our truck to get the best gas mileage. Brakes plugs and wires you name it im cleaning it or replacing it. We have both made extended trips before she has traveled from Idaho to Las Vegas and I have traveled the whole eastern coast for over 20 years for work. We are leaving Vegas to Nashville then on to Boston.
Any feed back would be welcome, we are also traveling in a single cab truck with two cats haha lucky us right.
Well thanks again

Welcome to RTA.

Have you considered doing part of your trip on old Route 66? You could take it from Arizona to Oklahoma City along I-40.

I had not thought about that but that would be awesome I have always wanted to travel route 66 !! Thanks :-)

Two cats! Wow, you're brave. Mine howl the whole way on the seven mile drive to the vet's office. I hope yours are well-traveled, or I'd consider leaving them at home with a friend to visit each day and feed them. I'd even prefer leaving mine at a kennel before taking them on a road trip. It would be far too stressful on both my cats & me for them to travel.