Compared to what your rooms are; mine are really tiny. One is about a 12 x12 and the other a little smaller. The smaller room has a full size bed and dresser in it and my small gracie frame. I almost made both of my rooms my sewing/office but my daughter and her family often spend at least one night every week or so. Plus, my bedroom is upstairs and sometimes I don't feel like going up the stairs, either due to being really tired or when my back or legs act up so it's good to have it. The other room is kind of crowded but I have room to do it all. My sewing table has the one end up against the wall in the center of the room and goes right out into the center of the room. Everything else is around it. The wall in front of it has the cubes from Walmart, the ones with 9 cubes each, I have 4 and they are stacked 2 high, some with canvas totes others not. I put pictures on the totes as to the contents or projects so I don't have to pull them out each time to see whats in them. I also have my small TV in one cube. Beside that is one of the tall wood look bookcases you can get from Office Max, etc. The center shelf doesn't move but the rest do. I went to HD and had them cut me more shelves so they are closer together and I could fold my fabric to fit each shelf and could separate the color and type of fabric better plus the stack isn't so tall that when you need something at the bottom it messes up the whole stack. On top of that I have the plastic zippered bags that my comforter came in which has Christmas fabric in and other fabric that I don't often need to get into but with the bags being clear I can easily see whats there. Under the bed in the other room I have put bed risers and long under the bed totes with my large pieces of fleece. My friend sent me boxes of it and I only have fleece in there so I won't forget whats there. Before I set up my bookshelves with my fabric I always forgot what I had. I wouldn't worry about an attached bathroom making the decision. None of my rooms have an attached bathroom, they are all out in the hall close to the rooms. You could always make one room for all of your fabric, cutting table ect and then set up your machines or even your backup machines in the guest room. Then if you have guest it wouldn't take much to get it ready. If you have a certain machine that you do most things on then keep that one in your sewing room so if you do have company you can still sew.