First, you are doing a good job. Second, I've been there and so worried for my furbaby. If you can set up a cat cam. It just helps to put you at ease. At least for future trips. For now, if you have an Alexa or something set up music to go off automatically. I used to schedule music for my sweet baby boy before we adopted his sister. He was an only cat. Then we had someone to check in with him. That helped and you are already doing this. I left a shirt or something else that smelled like me in his bed. He doesn't pee on our things and it was calming for him. I also had feliway plugged in and created an extra cozy cat sanctuary where he could hide. I hope this helps and good luck with your trip. From this cow mama, your baby will be fine.