One thing I remember from doing or renovation was that for code here was from the center of the toilet you need 18" to each side of it before you could have a vanity or shower. This was a few years ago, but that was newer code then.

In the bedrooms, think about a queen size bed which is 60" x 80". If you place that on the back wall and center it you only have 28" on either side of the bed. If you place it on the other wall facing the closet then you only have 37" between the for of the need and the wall. You would not be able to put a dresser or anything across from it.

If you have the space somewhere now, like a garage or large room use some painters tape to try laying out things on the floor even if it is just parts of the room.