How to help my dog when we travel with him?

We travel often to visit family or vacation. We like to bring our dog (Border Collie) as to not leave him in a boarding facility alone. He's always fine in the car and in the new place. However, the moment we cage him up and leave (for any amount of time), he freaks out. He barks/cries very intensely and does not stop. We've tried so many things, but nothing that works yet. We've tried giving him a lot of exercise before we go, making the place feel at home (unpacking our stuff) giving him his normal toys, leaving for a short amount of time and coming back (to show him he's not being abandoned), even tried the dog melatonin/hemp treats. Nothing works, he doesn't stop barking (even in places he's been many times like our parents house). We've even used a camera to check and he does not stop the entire time we're gone. We've moved once since getting him and he did the same thing, but stopped after everything was moved in and we had been there for a couple weeks. He's also been boarded a few times/stayed with relatives a few times (in case that has any impact). Does anyone have advice on how we can help him?