Keep in mind this is essentially a work-in-progress because there are sections of the house we've not seen, including a room behind the kitchen, a third bedroom on the first floor, and an upper level. Based on the layout of Cameron's room and the hallway outside of it, I believe her room is upstairs and either Derek is using that 3rd bedroom on the 1st floor (and we just haven't seen him in it yet) or he probably soon will be if he stays with the Connors.
If you have any questions about the layout or think something is wrong, let me know. The images are all the same, just different sizes. Take your pick:
Connor House Layout: 800 x 445 png
Connor House Layout: 1000 x 556 png
Connor House Layout: 1500 x 834 png
A fun thing I picked up from doing this (read no further if you haven't seen "What He Beheld")...
At the end of the finale, Sarah looks out John's window when she hears the explosion, but that window faces another house, not the street. The jeep would have most likely been parked on the kitchen side of the house (which is where they seem to come and go from most of the time) and there's no way she could have seen anything from that window.
NOTE: a revised version of the layout that has Cameron's room on the main level is available here.