Weird, I fixed the photo and it fixed your quote too. Not sure what happened, so I just reattached it.
I was wondering about a door to the crossover, but then I remembered you only mentioned the green and red walls at one time. I assume the wife will not want to see through to whatever will be on the other side of the wall, but curtains can take care of that. I'd be inclined to consider a picture on a section that swings into the room.
If you're up to the challenge of adding a lift up or lift out bridge, you can handle a removable access hatch, you just have to plan for it when you design the framing. There are plenty of techniques available to hide seams, but that all depends on your choice of landscaping. Oftentimes it's a sidewalk, road or parking lot.