Well some won't agree with me, but this is how I see it. I think you should stay where you are. If you move back into the house it is going to really do nothing more than cause her anger to hit the roof. You aren't to fear her anger and that is not why you stay where you are, okay? If I'm understanding what you wrote, you are very near the house....maybe in eyeshot? She's already wanting to know what you are doing--and I think you could continue to use this setup to your advantage.
If you move back into the house, it will push any progress backwards several weeks due to the anger she'll have...and she may not get past that. I know if I were that WAW it would not be a good move for the H. Every stitch is a bit different, and this is how I see your's as being the exception.
Anyway, I don't see it being worth it when you are near enough that you can live in peace and out from under that kind of stress. If you were under the same roof, she would know exactly what you were doing all the time, but living right next door.....she can only wonder what you are doing....who you may be talking to, etc. It's an opportunity to make mystery work for you.
Everytime she sees that little building, she'll know that she has no right to say anything about your life now. You are free to do whatever, whereas living under the same roof....could cause so much more tension.
If handled correctly, you are in a position that could start another R with her. But remember, just as she can see where you live....so can you see her house.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!