Any architectural types lurking? I drew up some before and after plans in Google Sketch and wanted to get a second opinion on my reconfigure of our master bedroom suite.
My father was a contractor and I worked with him when I was younger.
The first thing you need to do is to identify certain aspects of the structure. These aspects will greatly influence the cost of the renovation or it's design.
The first is load bearing walls. These are the outside walls but also includes inside walls that are used to actually hold up the structure.
Altering these walls for windows or doors is possible but will add cost and time to the renovation.
Wet walls. These are where your water, sewer and vent lines are run. So making changes here will require altering those systems and add more cost.
Adding partitions. If you are working on a wooded structured floor and want to add partitions you will need also add floor joists in the existing floor to carry the load.
Plumbing. Adding or altering your plumbing may also require some structural work to the floor or ceiling to support those changes or allow the plumbing to be done correctly. Adding a bathroom usually means adding a wet wall which is a 6" wall that allows you to run the proper pipes in it.
Electrical. Depending on your service you might be limited to how many new circuits you can add.
So my advise to is to identify these items and draw your house as it sits with just these elements in it. That way you can easily see the consequences of different design changes which will better help you control costs and stay within a budget.