I used to live in this house (without the mentioned modifications of course) for 5 years. I thought the office over the garage was really cool and that attracted me to the floorplan. However, that room was very hot and it really become unusable. There is poor air circulation in that room as well. There is only one window that opens and it is on one of those cranks, so you can't get it open all the way. There are two doors and I had to keep both doors open to get any cooling in the room. It is on the same A/C zone as the upstairs and the thermostat is in the house. So, if you put the A/C to say 68 degrees, it will turn off at 68 when the upstairs zone is 68 degree despite it being 78 degrees in the room above the garage. There is no way that I would ever convert that room to a master bedroom. We talked about putting a door to gain access to that room from the sitting room because the only way to access that room was to go outside in the balcony. We didn't do that because the media nook was the only access point and we already spend money on a build-in. If you are considering doing this, you really need to get a 3rd A/C zone just for that space. It will be unbearable without it.