move the switches if you have to (see last picture) or do a multi 4-way box.
go all the way up to the ceiling, over the window, and stop where the peninsula cabinet ends, or take it all the way out to the countertop. if you do that, take it all the way up and stop w/the door border. you can choose to stop at counter height(over to the door trim) or take it all the way to the floor.
too me, it looks like you ran out of tile if you stop half way up the window (you don't have the much to do above it anyway) or if you stop under the first shelf. white subway is cheap. buy more and do the entire thing.
Q