Cake by the Lake

Normal sudoku rules apply. Colour some cells green (land) and some cells blue (lake). All cells of the same colour must be orthogonally connected. A 2x2 area may not be all land, but it might be all lake.

LAKE: Lake cells must not touch the edge of the grid. The value of a lake cell equals its row number plus its column number, regardless of what digit appears in that cell. Eg: If r4c2 is lake then its value is 6.

CAKES: The value of a cake cell indicates exactly how many cakes have that value.

SAME DIFFERENCE: Adjacent values on a turquoise line always have the same difference. This difference must be determined for each line.