It's really nice that you're looking for ways to support your girlfriend!

Some ideas:

1. Your idea of putting everything work-related into a container can still work for someone who can't visualize. The concept still makes sense. But for me it helps to write things down on paper to reinforce the idea of ignoring work-related stuff until Monday.
   

I have a little calendar/planner sitting on my desk, and if I think of something work-related on the weekend, I write it down on the "Monday" section. That tells my brain that I'm planning to deal with that problem on Monday, so I don't have to worry about it on the weekend.

For the same reason, I keep a little notebook and pencil next to my bed. I often think of new ideas at night, and then I can't sleep because I'm worried that I'll forget something important. If I write it down in the notebook, then I know I won't forget it, and my mind can let it go until morning, so then I'm able to fall back asleep.

1. The best way to get your mind off work is to put your mind onto something else. If you have a hobby that takes a lot of mental focus, such as art, games, music, or sports, then you can forget about work for awhile. For me, I take a pottery class, and it takes a lot of focus to make pots, so there's no room in my mind to worry about other things. Creating things or learning things keeps your mind too full to worry. Even if it's only a few hours break from your worries, it does help refresh your mind. (But if you're feeling exhausted or burned out from work, it can be hard to find the energy to do something creative)

2. Exercise is a good way to relieve stress. Are there any activities you like to do together like taking walks or playing tennis?