A quick update on this:
I tried putting Blue into the travel box again, this time I tried in early evening since last time I tried was mid afternoon and I thought maybe if he was more awake, it would be less stressful. He seemed happier at first, I think maybe because he found the food right away and started just pouching food, but as soon as he’d pouched some food and wanted to go stash it, he started acting agitated again, I guess because he wanted to go back to his house and stash it all. So I immediately put him back.
I hate doing this, I don’t want to disrupt him and stress him, but he needs to move safely! I just wish I could talk hamster and tell him he’ll go back to his house as soon as we’re done driving.
Another idea I had was to connect his bin cage to the travel box via tubing and then let him explore on his own. But I’m guessing he won’t be interested in the small box when he’s got his big house and his normal nest and food stash, so I don’t think that will work and I’m reluctant to keep trying loads of stuff if I’m just going to stress him more
I’m getting desperate trying to work out how to do this without being cruel to Blue. Any thoughts about moving house with hamsters would be appreciated. Thanks all.