I have an actual sewing kit that is both my main set of stuff I use as well as what I take to my regular work group or classes. I also have drawers full of things that I take in and out of the kit as needed for the projects I have going on. Sadly, my Minions carrying case is loosing its usefulness and I'm switching over to a clear plastic toolbox shaped kit with nice secure hinges and latches.
I'm also a believer in slate blue/gray thread and camel along with white and black as being good enough for just about everything. Thread usually stays in its own drawer at home.
Don't forget the seam rippers!
I get little keychain measuring tapes from the dollar store or as souvenirs and typically have one in my purse, but if you don't usually have such things when you have limited rulers a long measuring tape can be handy. I actually prefer the big heavy hardware store type with the ability to hold the position in place, but a simple coiled up long tape has come in handy more than once.
About 2 years ago now my friend gave me a modern Bernina 820, a huge heavy computerized machine. She bought a used box from the dealer with all the appropriate packing materials and we packed it up. Due to where she lives/physical issues her preferred method of shipping was USPS and it cost about $150?? to send from outside of Phoenix to next to Seattle. There were no issues whatsoever from the shipping, but if I was going to drive, my sewing machine and my computer usually go in the car with me.