I have done two proposed floor plans for your second home.
First proposal - open floor plan - living room, dining room and kitchen all together, here we have double bedroom for you and your wife and another single bedroom for your four year old son.
Explanation of what is changed from the existing condition:
1. position of the bathroom, so we can make bright bedroom for your son.
2. position of the bedroom wall, so we can add door that will lead us to the son's bedroom.
3. storage room is a little bit smaller, because here we have add the position of the bathroom.
4. removed french doors, so we can make an open plan.
Second proposal - open floor plan - living room, dining room and kitchen all together, sleeping area for the son as a part of the bedroom, but there is still some privacy by enclosing the single bed with wood panels.
Explanation of what is changed from the existing condition:
1. storage room is a little bit smaller.
2. bathroom is in the same place, but becomes a little bit bigger.