First design :      The kitchen, living room and dining room are all rotated.
                           The kitchen and dining room are closer.
                           With the bay window over the sink,you can also grow herbs or
                            start peppers and the like there and maybe put a bird feeder right outside.
                            People can sit at the snack bar and look out the patio doors or still be part of
                            the living room.
                            I would suggest using a thicker wall between the master bedroom and living room.
                            Instead of 2x4, a 2x6 wall with insulation will reduce noise from people talking or
                            the television.
                            Since there is no basement, a central air system can be place where the stairs down would
                            be.  Hot water heater & a stacked washer/dryer could go in the mudroom area, or a freezer.
                            Extension can be troublesome (expensive, wind catches, energy sucks, point of stress for
                            foundation cracking during house settling.)